I know I posted questions bout a 351W I was planning for a kitcar but that is put on the back burner as I am looking into upgrading my daily driver. The 351W in there is a 1978 smog motor rated at 145hp and 200trq. I dont plan on directly building this one up since its still running but thought about getting either a block or a block kit ready to go and then put the cam and heads on it.

Anyways this is what I am looking at, just wondering about opinions on this since this car is a daily driver and I am not seeking a radical engine build up just something more than stock since it sucks having a 351W and your not able to spin the tires on drive pavement in a straight line but on wet roads you can spin them all day with just a hair touch on the throttle.

-Bore 4.030"
-Stroke 3.50"
-Heads World Products Windsor Jr. 58cc chamber 180cc intake port volume, 1.94"/1.600" Valves
-Intake manifold either oem 4bbl or Edelbrock 3783 aftermarket manifold with the Edelbrock 8053 4bbl EGR plate, might not run EGR valve but the plate will raise the carb up to reuse the OEM aircleaner housing.
-Pistons forged aluminum 24cc dished
-0.020" deckclearance
-Static Compression Ratio 8.678:1
-Dynamic Compression Ratio 8.658:1
-camshaft XE250H grind - 206/212 @ 0.050", 250/260 Adv., 0.461"/0.474" Valve Lift, 110 LSA
-Hooker Super Comp headers full length 3" collector with 3" to 2 1/2" header reducer and 2 1/2" dual exhaust with H pipe and dual WickedFlow MAX life time stainless steel straight flow mufflers
-600CFM Vac Secondary carburetor part # 64-3397, Ford 4bbl Holley remanufactured carb, 600cfm with hot air choke as well as dual fuel boal vents so I can maintain the OEM charcoal canister hookups for that "OEM" look.

Estimates I have done is putting it around 290ish hp @ 4,500 rpm and 380ish trq @ 2,500 rpm

Only a few points that bother me that I am not sure about.

First off is the pistons, I dont know if I should try to track down some cast iron heads with bigger combustion chambers and use a smaller dish or flat top piston or if it doesnt matter performance or efficency wise to run a huge dish to drop the compression down to run off 87 - 89 octane pump gas.

Second thing is the camshaft, I know it has a smooth idle but I dont know if I am misinformed or what but my understanding is that the LSA is what dictates what kind of vacuum, powerband, and exhaust sound quality you will have. This one here should be a smooth idle camshaft but the 110* LSA is making me think the exhaust should have a noticeable idle like a very slight lope sound to the exhaust. I dont know if that is true or not but I would surely hate to run headers and those straight through mufflers and spend on the money on exhaust and have something that doesnt sound worth a damn.

Third is the carb, a 357.2 cid engine (0.030 over bore) turning a max of 5,000 rpm (engine never goes past 4,500 currently when floored passing gear kicks out at 60 mph @ 4,500) for street I am coming up with 439.02 CFM @ 85ish percent VE which is just a generic estimate seeing as DD2000 which I dont fully trust is showing a max of 83% VE @ 4,000 rpm and below 80% between idle and 3,000 rpm. I know running too big a carb can be worse than running too small, so I am just wondering if a 600cfm would be too much. Currently theres a 351 cfm 2bbl on the car from the factory and runs fine and the same summit calculator lists 432cfm at 5,000 rpm and at 4,500 its coming back as still 388 cfm. So I just dont know on this, if it will work though abit oversized the vacuum secondaries might not kick in that often resulting in better fuel economy and I might be able to run the idle mixture screws leaner than what I currently have getting slightly improved city economy.

I dont think I am concerend about anything else other than the three above. I know it should be an improvement over the 145hp/200trq oem engine and should run just as good but with almost 400 ft lbs of trq estimate if not actually being more than my estimates, the car should accelerate and pull a whole lot better. Like wise I feel with a 4bbl carb I should see a improvement in gas miliage keeping foot out of throttle over the 2bbl as well as the fact that the heavy 4,000 lb car with the 2.50:1 axle ratio should move better with less throttle with more power. I know I could go to the trouble of swaping the rear end out geting rid of the FMX transmission and upgrading the trqconverter but I love how the car drives now and in realty just would like to upgrade this engine. Might not happen over night or very soon due to the economy but doesnt hurt for me to do my research and plan ahead of time.

Its too easy for me to just go radical and build a hopped up race engine when selecting parts but it is something totaly different to me to try and build a engine that is hotter than stock but will work with what is already there drivetrain wise and ignition wise. If it will all work then I am doing pretty good I think cause the highest hp 351 was 290hp and 385trq with a 4bbl and a 10.5:1 compression back in 69. But ill post what I have or ill end up with a freaking book here.

 

Nice combo there. I think you can afford to push compression up into the mid 9:1 territory though, and there's absolutely no need for forged pistons on this type build, hyper or even cast are more than sufficient so use whatever you can find to get a more reasonable static CR.

No one cam parameter determines the powerband or idle quality it's all things combined. 110LSA is short but so is the intake duration at 206 deg so overall this combo won't be as radical sounding at idle as an all out performance motor, but then the whole powerband is below 5000rpm which isn't hi performacne territory either.
I think your carb sizing is fine, in the real world a little oversized on the cab is nothing to worry about.

 

I heard about being able to run either cast or hyper, but I was leaning towards forged since I do drive the car hard sometimes. Just want something that wont break down if I drive the car alittle hard on the road.

Ah ok I remember reading somewheres that the LSA determins the idle quality. Not that it matters though I would like a nice sounding exhaust, nothing radical but something that says I have a V8 under the hood. Also dont want it to sound like a 5.0 mustang They sound ok but I just dont like that smooth humming sound exhaust.

Yep and I would consider upgrading to a 6,000 rpm redline camshaft but I love lugging this old 351W at 1500 rpm around city running 45mph or lug the engine down to 1000 rpm and cruise around at 30 mph.

Also if I were to push compression up to around 9 - 9.5 to 1 what kind of fuel octane would I be looking at with cast iron heads? I would prefer to keep it between 87 and 89 octane since alot of the gas stations here dont even stock 93 octane anymore and the few that do half the time they are selling 89 octane at 93 octane prices. If I could get away with higher compression I would go for it. I do know I am wanting to run an aluminum Flowkooler high volume water pump that flows 30% more water below 3,000 rpm and stock flow above to reduce overcooling on the highway. Well 2,500 rpm here is highway speeds of 85 - 90 mph. But since I upgraded my radiator when my orignal one went out to a 3 core heavy duty my oem water pump just doesnt push the water through this radiator like it did the old. Funny how a 3 core copper radiator was almost $50 cheaper than the oem standard duty 2 core coper radiator.

 

Ok I have made a big mistake, my dynamic compression figures were done wrong. I was using the EVC timing @ 0.050" + 15 instead of using the IVC. So where I was saying I was at 8.782:1 static compression my dynamic compression is really just 7.968:1 not 8.762:1 like I said. Secondly I noticed I was using the compression figure I came up with for a stock bore 351. I had two figures one for a stock bore and one for a 351 that was 0.030 over. I mistakenly said the wrong one.

But besides that I have been doing alot of reading and research for the day here and I have some things to add.

I desided to do a search for Dynamic compression to get an idea for what the avg ranges are for aluminum and cast iron heads. Well I seen alot of different ranges, those from 6:1 to 7.5:1 as being optimal for cast iron heads on pump gas to some talking about quench and that you can run as high as 9.5:1 dynamic compression off pump gas with a properly designed engine taking advantage of quench.

Ok well I figured let me look into quench cause Ive heard it said alot but never looked into it and as it stands. Basically me using the huge 24cc dished piston has a higher chance at causing detonation issues because it doesnt take advantage of quench. Which I have been reading is the mixing of air/fuel created by turblence as the flat top of the piston comes close to the flat part of the head quenching the air/fuel mixture. Well with a dished piston like this there will be no real optimal quench so I wont be mixing the air/fuel mixture as well as if I went with something like say a flat top piston. This would from my understanding cause hot spots to form as air/fuel mixture becomes lean and rich in pockets.

So basically I need to increase my compression by going with flat top pistons which will raise compression but improve quench. Which in theory as I have been reading keep the air/fuel mixture evenly blended and prevent lean/rich pockets which can cause detonation and knocks.

The use of plain flat top pistons without changing anything else keeping the same deck clearance, same heads, same head gaskets, same rods, same stroke, and same camshaft I come up with the following.

Static Compression : 11.448:1
Dynamic Compression : 10.355:1

Which I honestly dont think would run off pump gas even 93 octane.

So I figured the same thing up with flat top pistons but with two valve reliefs like oem pistons. With 4.8cc valve reliefs I come up with the following.

Static Compression : 10.778:1
Dynamic Compression : 9.756:1

Which this dynamic compression sounds better than with plain flat tops but I just dont know about running off 87 - 89 octane. I know in theory with the flat top the quench against the heads will mix up the air and fuel mixture better preventing hotspots and uneven burning forming and if I do have the cast iron heads drilled to open up the EGR valve ports in theory when driving the exhaust gas will take up part of the cylinder to result in a lower combustion chamber temperature. This in theory should reduce the formation of NOx by keeping cylinder head temp down. So all on paper in theory the use of 10.778:1 static compression with 9.756:1 dynamic with better quench, along with the use of an EGR valve should allow this engine to make power and run off 89 octane gas. But theory and real world doesnt work alike though.

I dont know what kind of pistons I used in the other design I did but I have another setup saved that is using Ford GT40X heads, I think their aluminum and I have a static compression ratio listed of 9.33:1.

But if I am understanding this site correctly I dont have proper quench though with the smallest gasket I can get recomended for these heads are 0.041 and it calls for a static quench distance of 0.040. Means I would have to have my piston 0.001" above the deck just to get 0.040" quench height. So in this situation based off the total quench distance I have of 0.061" I would run the risk of detonation on higher compression ratios as described on this article.

http://www.beckracing.com/page05.htm

 

I suggest you see what actual pistons are available and model those, they may not produce optimum results on paper but the real world results are often quite acceptable. That said I think 9.5-10-1 static range is about the maximum that will run on regular pump gas with a carb. There are lots of pistons that will deliver that with 60-64cc combustion chambers so maybe that is what you need.. unless you can have a set of pistons customized to give you the ideal quench shape and a large enough dish to keep static CR in line. Maybe start with flattops with 2 eyebrows and have the land between the eyebrows carved away to leave a D shaped dish on 1/2 the piston.

 

I am looking at other pistons right now. So far with the stock connecting rods the best I can get is a 0.01" deck clearance with a 9.500" deck heigth. That will give me basically 0.051" quench which is still 0.011" too high for what I see recomended. I looked at the headgaskets but the world heads only recomend two headgaskets for their heads and the thinnest one is 0.041" itself. I am like thinking sheesh I only wanted top end upgrades and cam with everything else stock with a 0.030" overbore. Looks like now to obtain a -0.01" piston deck heigth would be to go with longer rods or deck the block which means the intake manifold would have to be shaved slightly to fit right.

To be honest the more I look into this the more I am just thinking about staying stock. I am seeing it as you cant do a very mild street build. To get the best of everything you pretty much have to redesign the engine specifications to get it to work. It would also suck for me to just say screw it and build it like this only to find out the thing pings like hell on 93 because of the excessive quench which is more suitable for a engine that spins past 6,000 rpm than on a engine that spends its life between idle and 2,500 when its not floored. Not to mention the cost to build the engine would be a waste because who the hell would buy a engine that pings on pump gas.

 

Ok here are some of the differences you are looking the cast aluminum piston would be more ideal for you. My guess driving hard means romping from red light to red light yes making around 4500rpm at the normal and maybe up to 5000 to 5500 a cast aluminum piston is light and more dimentionally stable compared to a forged piston which is heavier and less stable. Now that being said a cast piston is much more brittle and will break down sooner under a heavy load for long periods of time. So if you want to use something other than a forged piston the hyper models would probably be a great option for you. At the same time however many companies are making pistons so cheap in their forged versions that it is cheaper to buy becuase to make a forged object it is easy than to cast one which takes large smelting furnaces special equipement and special training of certain people who like to work in hot sweaty sausage filled enviorments where a forged one is made by hitting a couple of buttons on the CNC lathe and walking away to grab a cup of coffee. In my opinion a forged piston is over doing it for the engine you are looking at but here a few options for you 61 to be exact snoop to your hearts content and let us know what you think of course this list was built by using the 4.030 number instead of exactly 30 over at 4.032.
1974 - 3.500 in. - 4.030 in. - Ford small block Windsor - 5.8L/351 - FORD - Pistons - SummitRacing.com

Now on to the cam shaft lobe seperation angle with the other parts of a camshaft play a huge role in the performance of your machine most companies have decided for us after many years of testing customer feed back and what not that a standard LSA should be 110 as it offers a good compermise between idle quality and power numbers.

A small LSA offers torque to the low end RPM, increased max torque, a narrow power band, higher cylinder pressure, an increased chance of knocking, increased cranking pressure, increased effective compression, decreased vacum at idle, decreased idle quality, increased valve event overlap (open and closed), natural EGR increases, and finnaly a decreased piston to valve clearance. So yes you get more torque better usable compression and a lope at idle, but you have a higher chance of knocking a larger chance of blowing oil everywhere when your dipstick decides to make a run for it and less vacum (becuase we all want more sucking).

Now there are disadvantages to a large LSA as well your torque band moves to a higher RPM making it slightly harder to tow things, reduces usable compression and the like but we also need to look at the cam itself.

An advertised LSA is not always what it seems you would think that a cam company actually measures it's cams to determine LSA but it is done of certerline modeling not the actual lobe. This is one reason why you MUST absolutely MUST degree your cam t know what you are getting larger duration cams (More egg shaped lobes) actually will have a larger LSA than is advertised on their cam card while the lower duration cams will have even smaller LSA's

Another way to explain everything is thus.

A camshaft consists of intake and exhaust lobes, and a key consideration when designing a cam is the lobe separation angle, sometimes also called the lobe displacement angle, or lobe spread. The definition here is simply the distance in degrees, as measured on the cam, between the point of peak lift on the intake lobe and the peak lift on the exhaust lobe. There are several measurements found in a cam's specs, which give clues to the performance characteristics of a given grind. Some, such as lift and duration, are easy enough for even the neophyte camshaft connoisseur to understand. These are often the only specs considered when selecting a cam. Really, for any given lobe, that's all there is, lift and duration, and the two can be related to map the profile of a lobe throughout its lift cycle. Though lift and duration alone can fully describe an individual lobe, each cylinder of an engine has intake and exhaust lobes, and the timing of these events relative to each other have a significant influence on engine performance. Neither lift nor duration gives any clue as to this aspect of a cam's design. Lobe separation angle does.

Simply put, the lobe separation angle (LSA) is a measurement of how the intake and exhaust lobes are phased with each other. To establish the position of each lobe, the traditional reference point is where the lobes reach max lift. Picturing the end-view of a cam as a circle with 360 degrees; the lobe separation is a measurement in degrees of the distance between the max lift on the exhaust and intake lobes, respectively. Note that degrees of lobe separation angle are given in a simple degree measurement at the cam, in contrast to how duration is measured as degrees of rotation of the crank, which turns at twice the cam's speed. With this in mind, lobe separation angle is said to be in cam degrees, while duration is quoted as crank degrees.It's not astonishing to us that lobe separation will have a big impact on performance. After all, the valve timing events have to occur at the most advantageous moments to glean the desired results from an engine combo. Obviously a LSA of zero would have the intake and exhaust valves open and close at the same time and even we know this won't work. Cam grinders are pretty sharp on this subject, and have found the sweet range for LSAs in the range of 104-115 degrees for most applications. Typical off-the-self aftermarket cams will have a lobe spread between these values, with the greatest number of offerings falling toward the middle of this range. Coincidence? We think it's a pretty safe bet that they've got a handle on what works, and grind their cams accordingly.

Even within this relatively narrow range, the lobe separation angles will affect engine performance. The following chart gives some of the general haracteristics you'll see with two otherwise identical cams ground on narrow or wide lobe separation angles, assuming they are installed with the same amount of advance.A camshaft consists of intake and exhaust lobes, and a key consideration when designing a cam is the lobe separation angle, sometimes also called the lobe displacement angle, or lobe spread. The definition here is simply the distance in degrees, as measured on the cam, between the point of peak lift on the intake lobe and the peak lift on the exhaust lobe. There are several measurements found in a cam's specs, which give clues to the performance characteristics of a given grind. Some, such as lift and duration, are easy enough for even the neophyte camshaft connoisseur to understand. These are often the only specs considered when selecting a cam. Really, for any given lobe, that's all there is, lift and duration, and the two can be related to map the profile of a lobe throughout its lift cycle. Though lift and duration alone can fully describe an individual lobe, each cylinder of an engine has intake and exhaust lobes, and the timing of these events relative to each other have a significant influence on engine performance. Neither lift nor duration gives any clue as to this aspect of a cam's design. Lobe separation angle does.

Simply put, the lobe separation angle (LSA) is a measurement of how the intake and exhaust lobes are phased with each other. To establish the position of each lobe, the traditional reference point is where the lobes reach max lift. Picturing the end-view of a cam as a circle with 360 degrees; the lobe separation is a measurement in degrees of the distance between the max lift on the exhaust and intake lobes, respectively. Note that degrees of lobe separation angle are given in a simple degree measurement at the cam, in contrast to how duration is measured as degrees of rotation of the crank, which turns at twice the cam's speed. With this in mind, lobe separation angle is said to be in cam degrees, while duration is quoted as crank degrees.It's not astonishing to us that lobe separation will have a big impact on performance. After all, the valve timing events have to occur at the most advantageous moments to glean the desired results from an engine combo. Obviously a LSA of zero would have the intake and exhaust valves open and close at the same time and even we know this won't work. Cam grinders are pretty sharp on this subject, and have found the sweet range for LSAs in the range of 104-115 degrees for most applications. Typical off-the-self aftermarket cams will have a lobe spread between these values, with the greatest number of offerings falling toward the middle of this range. Coincidence? We think it's a pretty safe bet that they've got a handle on what works, and grind their cams accordingly.

Even within this relatively narrow range, the lobe separation angles will affect engine performance. The following chart gives some of the general characteristics you'll see with two otherwise identical cams ground on narrow or wide lobe separation angles, assuming they are installed with the same amount of advance.

 

Looking at that link, the one I am liking the most is this one. Only because with a 9.50" deck heigth it provides a 0.010" deck clearance. The dish would negate the point of quench to help cut down on chances of pinging but what I have seen someone say is that quench below 0.050" is fine with 0.010" with this piston and the 0.041" head gasket I am at 0.051". I guess World Products wasnt kidding saying this head is a bolt on for the 302 with their shorter deck heigth they could get quench easily. Not with a 351 thats for sure. I might go with different heads for all I know considering this. Something that will bolt onto a 351W and be able to tune it for proper quench as well as being cast iron. Not sure how well aluminum heads would stand up to be painted engine color and heat cycled.

Sportsman Racing Products 149606 - SRP Ford Small Block Dish Top Pistons - Overview - SummitRacing.com

But now the pistons I were looking at are these which gives me a 0.020" deck clearance.

Sportsman Racing Products 138722 - SRP Ford Small Block Dish Top Pistons - Overview - SummitRacing.com

or this one which would give me more compression

Keith Black/KB Pistons IC729-030 - Keith Black ICON Premium Forged Pistons - Overview - SummitRacing.com

But this one is slightly less cc dish than the second one but its a D shaped dish.

Keith Black/KB Pistons KB181-030 - Keith Black KB Performance Pistons - Overview - SummitRacing.com



The camshaft the specs says to run it at 106* crank center line which would put it 4* advanced. The description also says "Hydraulic-Very strong torque, excellent mileage, smooth idle."

35-230-3 - Xtreme Energy

But if DD2000 is even close (accurate specs on a oem stock 283 came out to 198hp and it was rated at 195 and my 145hp rated 351W came out at 152) it is showing manifold pressure over 14 PSI. But if I could get atleast 15" of vacuum out of this camshaft I should be fine. I got the dist advanced to get 20" to get the engine to run smooth. I know I got alot of vacuum powered stuff but 15" should be enough to operate power brakes. If not well then I dont see how they can list this as a street cam.

 

I just ran the camquest program which is a cam selecting program from Comp Cams. I put in the engine specs as I designed, the Windsor Jr heads, the 10.78:1 compression with the 0.020" deck clearance flat top pistons with two valve releifs, and headers with mufflers.

It came back with four hits as Great fits. They are as follows.

35-416-3 Dual Energy - 203/216 @ 0.050", 0.434"/0.467" Lift, 110* Lobe Centerline, 106 Intake centerline - Good Torque, Good Miliage, Excellent High End Horsepower Smooth Idle. 1,000 - 5,500 RPM Range

35-230-3 Xtreme Energy - 206/212 @ 0.050", 0.461"/0.474" Lift, 110 Lobe Centerline, 106 Intake centerline - Very Strong Torque, excellent mileage, smooth idle, 600 - 4,800 rpm range

35-231-3 Xtreme 4x4 - 206/214 @ 0.050", 0.448"/0.483" Lift, 111 Lobe Centerline, 107 Intake centerline - Excellent torque and throttle response, good 4x4 low end power, 1,000 - 5,000 rpm range

and the last great fit one

35-215-3 High Energy - 206/206 @ 0.050", 0.433"/0.433" lift 110 Lobe Centerline 106 Intake Centerline - strong torque and mileage in low RPM applications, stock replacement, smooth idle - 800 - 4,800 rpm range.

The same cam program does power output estimates and the highest estimate is the 35-416-3 dual energy one at 350HP @ 5,000 rpm and 462trq @ 2500rpm. The one I desided on, the 35-230-3 Xtreme Energy one, comps program estimates 342hp @ 4500 rpm and 465trq @ 2500 rpm. The stock replacement one, 35-215-3 high energy is listed at 330hp @ 4500 rpm and 458trq @ 2500 rpm.

So I think 35-230-3 is my better bet since the powerband is going to be pretty much there from idle. Only thing is like you said vacuum. I dont know how much vacuum this camshaft will create and I know I got vacuum assist brakes as well as vacuum doors on all in my heater plenum. Vacuum is even used to operate the hot water valve for the heater as well as the thermister that sends vacuum to the plunger on the aircleaner snorkel to either suck warm air from around the exhaust manifolds or through the ductwork out infront of the car. So I hope this camshaft makes enough vacuum for my application. I also noticed if I am below 20 inches of vacuum my vacuum parking brake release doesnt always release. So damn I might have to get a stock cam that makes high vacuum but Comp`s stock replacement is the same lsa as the one I am looking at now.

 

SO thinkin your all smart and junk with comp cams program huh well I raise you Dyno Sim 5 mwahah.

Ok now to the engine stuff and things. The comp program is great I loved it and I still use it for quickies. but for tweaking need something a bit more powerful. Now I am going to ask you a series of questions to get a baseline for you lie detector test.

Is your name Rusty_S?
Do you know of Comp Cams?
Have you found new head gaskets with a measured crush rate to determine final clearnce between your head and pistons with an appropriate bore size?

With 110 LSA you should be just fine for vaccum I am worried about your compression calculations with the information I have got from you here I am getting between 13.50 and 14.20 when I crunch some numbers so what I would like just to double check is this.

1)Head chamber volume.
2)Dome volume
3)Valve relief volume
4)Deck clearance at TDC
5)Head gasket bore
6)Head gasket thickness

Also if you want a full work up from my program let me know and I will email you with the results the resulting file from my simulations is far to large to post here. It even comes with handy dandy graphs to impress your friends!

 

ok lets see now.

1. World Products Head 57cc, Edelbrock heads I am looking at now 60cc
2. Flat top pistons no dome
3. 4.8cc valve relief volume
4. current clearance is 0.020". Seeking to drop it down to obtain around 0.030" quench celarance.
5. 4.100"
6. recomended gasket for World heads is 0.041", I see no recomended for the Edelbrock aluminum heads so I picked out a 4.100" x 0.038" headgasket.

With the world products head at 57cc with flat top pistons with 4.8cc valve relief with 0.020" deck clearance with 4.100" x 0.041" head gasket I come up with

Static : 10.778:1
Dynamic : 9.756:1

With the 60cc edelbrock heads with same 4.030" bore flat top pistons with 4.8cc valve reliefs, 0.020" deck clearance and 4.100 x 0.038 head gaskets I come up with.

Static : 10.479:1
Dynamic : 9.488:1

This is using this calculator which to get dynamic it has you enter the IVC ABDC degree + 15 degrees.

United Engine & Machine Co. Incorporated

But what I am reading about the whole quench and how it helps to cool the air/fuel mixture as well as mix the air/fuel mixture up better I am thinking if I can keep dynamic compression under 9.5:1 with aluminum heads as well as get a better quench I might be able to get away with 9.5:1 or less compression on 87 - 89 octane. Prefer not to run 93 honestly.

Problem is though the thinnest gasket I can obtain in a 4.100" bore is 0.038" which means to get 0.030" quench I would need to be 0.008" above the deck. But this online superchevy article on quench said basically any quench within 0.050" will be effective but more than 0.050" will have no quench benifit

 

Ok here is my only problem with what you said it was a chevy article not a bad thing there is always good information everywhere but they have different problems then we do the main problem fords are looking at is air turbulance typicly Fords do not get enough turbulance in the air to make for an effective burn what happens is a low pressure zone is created in the combustion chamber making one side of the piston fuel heavy leaving us off balance the way to correct this is some porting to the heads but that is a whole different matter.

The numbers I am running favor the 60cc heads much much better a lower comp rate at 10.48 which is right at what you were getting. I would be very happy with that myself. Now if you are looking at going to 9.5 area you should maybe look at either inverted dome pistons or larger combustion chamber heads. Either or will lowr the pressure dropping you down considerably plus the inverted dome should give you more turbulance to the needed areas. But 10.5 is a great number to work with. I understand the want to run lower quality gas since it is cheaper and this isn't a romp machine so that is something to consider.

Since you are running wedge heads and not hemi, disc, or pentroof I wouldn't say forget about quench becuase it is important but not as important as getting an even burn quench you are trying to get fuel evenly compressed around the combustion chamber but if the air flow isn't even to begin with quench takes a backseat til this is accomplished.

So right now with those parts I would go with the edelbrocks and the flat tops. I think this will give you a mean engine for just a stock pull over my cam different than yours and I am pulling more horsepower out of it. If you would like I can give you the numbers and you can give COMP a call when they open tomorrow.

 

I just ran the Edelbrock Performer RPM heads which are 60cc chambers as well so static compression wouldnt change. But wow, I am getting over 350 hp but sadly DD2000 is putting it at 5,000 rpm which is useless for me since the car shifts out of passing gear at 4,500 rpm and the camshaft that I am running is only 600 - 4,800 rpm so I think this is probably an error. But I am liking the 420 Ft lbs of trq @ 3,000 rpm. means if I am on the highway lugging at 2,500 rpm at 80 mph and wants to accelerate peak torque is pretty much 500 rpm higher than what I am cruising at. That is always good in my book.

The only thing that has me concerned is the quench part. Aside from that I can get the deck clearance to 0.010" but they are some brand of pistons I never heard of and all of them are dished. Which a dished piston the way I understand it would hurt quenching. Now I can get a 0.020" headgasket but it requires lock wires, its a expensive race only copper headgasket. Dont care to spend close to $80 for just one head gasket for a street driver lol.

But now if I want to drop the compression down I can go with a inverted dome or a D-Dish as they are called to drop the compression down but still maintain the flat piston top around the head to have an effect on quench. But as of now with 0.020" deck clearance and 0.038" gaskets I am over 0.050" so quench would pretty much not exsist for me. Now I have thought about running an EGR Valve since I know pumping the cylinder full of exhaust when driving takes up some of the cylinder packing the air in fuel in the remaining area keeping compression and power up for the most part but resulting in lower combustion chamber temperatures and hopefully preventing detonation. But I dont think the edelbrock heads have the ability to do that. Not to mention the carb I am looking at running is a OEM ford 4V at 600 cfm with an hot air choke and I think that edelbrock head doesnt have a exhaust cross over port. But thats no big deal though only reason I had my eyes on that carb is with a simple plastic vacuum line Tee I could connect the front and rear fuel bowl emission vents to my oem charcoal canister for a factory look. But cant always have everything got to compromise. If I could get this setup to make lots of trq for this heavy car and modest hp and run off atleast 89 octane fuel (middle grade) I would be happy with it. But I am going to be looking into it and I will be calling up Edelbrock in the morning to question about their heads and if their accessory bracket mounting locations on the heads are in the oem position compared to ford heads. I just planned on unbolting my accessories laying them forward and bolting them back on, dont want to take them all apart just to cut slots in the openings to they fit like with the world heads.

If I go with the hyper aluminum pistons from Keith Black the D shaped dish or reverse dome it only comes in a 22cc volume but keeping everything the same with those 60cc heads compression will be dropped to 8.752:1 static and 7.941:1 dynamic. Gonna plug in 8.752:1 and see how that effects the figures in my program. I am leaning towards the 10.5:1 since its 9.5:1 which with aluminum heads should run off 93 octane easily. Then if I run the high volume water pump I might luck out and get away with 89 octane.

Update

With the 8.752:1 I am getting 306hp @ 4,500 rpm and 387 trq @ 3,000 - 3,500 rpm which isnt bad considering highest hp 351 was almost 10:1 with a 4V and only made 290 hp in 1969. Now if I go with the edelbrock performer RPM heads witht he same compression I get 330hp peak at 5,000 rpm and 393trq @ 3,500 rpm. Not bad but for the cost if I can expect peak trq at 5,000 when never seeing that rpm I have to say better to stick with the E-Street entry level aluminum heads.

 

Sounds good let me know how it goes.

 

Will do I am taking notes here listing everything down and going through my engine books. What I am thinking is dont worry about quench but go with the 0.041" thick head gaskets with the flattops with the valve reliefs. It would lower the compression down some with the 60cc heads but it will still be at 10.4:1 static and 9.4:1 dynamic. But I will bookmark this topic so I can update it in the future.