O.K., I understand the overlap of the cam part but not the difference in the head "metal". So if I had two sets of heads with exactly the same components (valves, springs, seals, ect.) the aluminum heads would not be as sensitive to detonation, or maybe give me the detonation? I don't think you are crazy by any means, but it doesn't make sense to me, just thinkin logically I guess. You definately have my attention though. I am thinking very seriously about buying a new set of heads (World) for the build. When I do work the engine hard could I just add some Octane booster to help with the detonation? I have no problem running 89 octane because that is what I run in all of my vehicles. I totally agree about changing the time. That ain't gonna work for me. The Rev box, expensive, pain in the but, worth my time and money? Hey Kemical, I saw in some of the other forums you talked about MAF. What is that (mass air flow?) and does it only apply to EFI? Thanks for the reply Kemical!
Part of the purpose in running a higher compression ratio is so that you can run a bigger cam. Generally, the bigger the lift and duration, the more overlap it's going to have. You can have one custom ground with wider lobe centers to counter this though, but you can only spread em to a point. Aluminum heads are supposedly less sensitive to detonation, but I tend th o think that's just a theory. Once the engine's up to operating temps, the chamber's temps stay in a set range. The cooling system's efficiency plays a big part there. I know that the 331 I built, when I first started it, I had a tank of 87 octane gas running thru it. And I've never heard such a racket. That thing wasn't pinging, it was hammering rocks. I've run my 68 Merc's 390 with almost a similar comp ratio on 87 and it just pings with iron heads. Of course,they both have different cam grinds too and that plays a big part. It's just my opinion, but to me , if you're going to plan on towing heavy loads, frequently, I think iron heads will be more durable in the long run. If you get into pinging, you can use a higher grade of fuel, or back off the timing to adjust for it. Figure out the compression ratio you're going to have once you get the parts, then choose a cam manufacturer and call them to get a recommendation on what cam to go with based on your parts and what you want it to do.
Last edited by baddad457 : 07-08-2006 at 03:51 PM.
I had talked to crane cams about a cam allready but things have changed since then. I will need to call back once I have more concrete info. (like you said Baddad) due to some of the changes that I will be making. Do you guys recommend crane cams. I follow what you are saying about the detonation issues. Bases on what I have found so far, the aluminum heads are about $250-$300 more than the iron heads. I haven't really found a good enough reason, yet, to go with the aluminum heads. I mean if its gonna tear up my motor then yeah that's a good reason but if it's not then I'd rather not spend the extra cash. My original budget is allready crushed but I do still want to try to do things reasonably inexpensive (not cheap). What do you guys think about Pro-comp or scorpion roller rockers. Or would you suggest another brand of inexpensive roller rocker? Thanks again!
Another question, what do you guys recommend for headers. My machinist said to go with a 1 5/8" tube. What brand(s) will give me the best fit? 87' F-250 4x4 Dana 50 front end. Also, what's the scoop on copper head gaskets? My machinist said that he has never used them for one of his builds. Good not so good? It could help with the compression issue in addition to massaging out the heads.
the theory with aluminum heads is they disipate the heat better allow you to run higher comp with a less grade fuel. but like he said its all in the parts working together properly. Personally i wouldnt go above 9-1 just due to the way gas is so expensive and running higher grade just isnt practical anymore ya know. that comp would be fine with either head. I would go with BBK ceramic shorties. from what i have seen they have the largest collector opennings which for a stroker would be a good setup.
check out fu ll si ze br on co . c o m (no spaces) and do a search for 393 408 stroker and there is a guy getting ready to run them on his build. very nice and decent price.
I see what you are saying Kemical, I didn't look at it as a heat issue. I looked at the FSB.com site but I'm not sure that I found the right guy. Do you remember what his user id is? Also, do you have any input on the copper head gaskets? As far as the headers, they seem like a good header but are there any other brands that are a little less expensive or would I just be wasting my time?
jba, gibson, edelbrock are also good headers. I wouldnt pay any less then 250 for a set. headers can be found cheap but usually have leak issues, thin head flanges that warp etc.. the term get what you pay for really applys to this product.
If you have the time,and don't mind using used headers, you can run across great deals on ebay. I bought the nickel chromed Tri-Y's for my Ranger there for $85. Bought a used set of Doug's chromed Tri-y fox body Stang headers there for about the same price. And I've had others as well. Search for "Ford headers"
I havn't read this whole thread....but I'm the guy who TigerDan linked to and I can offer some help...
First off...
Using stock heads is not really going to work. When you pick a certain CI displacement - you're selecting a particular airflow requirement and torque output. A 10% increase in stroke yields a 10% increase in torque. When you select heads - you're determining where the tq is within the RPM range. The higher the flow on the heads - the further up in the RPM band the tq will be. You'll also create more horsepower in the process. A stock head is very restrictive as it is - let alone with a 393 and stock heads. It would still put out 400 or so ft-lbs of tq...but it won't make much horsepower and it will be at very low RPMs.
On a stock 351 with stock heads - it really starts running out of airflow at 4200ish RPM. With a 393 and all else unchanged - it would be around 3700ish. Do you want an engine that will only really operate between 1000-3700 rpm and makes like 200hp? It's also important to note that any RPM ranges given for parts (like an intake of 1500-6000 rpm) when used on a 393 will drop that RPM range by about 500 rpm. So an intake rated for 1500-6000 on a 351 will turn into about 1000-5500 on a 393.
I tried to get away with using GT-40Y heads (middle of the row and cheap) and then plan for switching to a much larger head later on...but with all the problems with my project it's all fallen apart. I'm probably not going to keep these heads...even though they'd work.
The best way to go about building this engine is to save up your money and do it right the first time and only do it once.
You don't need huge heads or what not but you need something that will flow a decent amount. You also need to have the cam, intake, and exhaust flow at similar rates. The better the match the better the power you'll make.
There are two aspects to building an engine....the shortblock...then the upper longblock (selecting heads, cam, intake, exhaust).
For the shortblock on a budget...you have two main options...
You can get a 400M crank and have it slightly ground at the machine shop to fit a 351W block. Or you can get a regular 3.85 stroker crank for about $250-$300. You can use stock 351 rods - and stock 302 pistons...but you'd probably need .030 over pistons unless your block doesn't need to be bored.
Good info. from all 3 posts, especially yours Mustang+++!
Point perfectly taken on the headers. I don't mind spending a little extra money if it will save me the headaches and embarrasement in the long run.
To be totally honest Mustang, I was starting to lean towards not doing the stroker at this time and just rebuilding the 351 with a couple of goodies. I might look a little closer at building a 460. One of my buddies has a couple of them as well as the trannies sitting around. I could at least get the trannie for virtually nothing. Something just hasn't been feeling right with the 393 project. Basically because I really did't want to get about $4k or more into it. To do it reasonably right, it looks like I will have to spend about that amount. I will have to sit down and make up a parts list to see what kinda money I'm looking at for sure. Then maybe take a different avenue.
I read some of your thread on your stroker. Man that sucks. I would be extremely P.O'd if that happened to me. Good luck with the new build. Hopefully things go better this time!
Again thanks for all the info., that was an awesome post. Kinda turned on a light bulb in my head.
World engines makes a kit to bore and stroke your 351W to a 460 with 600hp i don't remember what the torque is. After building engines for my grandpa who owned his own engine are racing shop we would take any engine but we did alot of chevy engines for the dirt track cars but we would take a 350 4 blot main block and bore and stroke it to a 396 and give them a 13.5:1 comp ratio, engle flat tapet cams, supper victor intakes, victor heads, over sized valves, JE or keith black pistons and the entire MSD system and run the cars on methanol and make on average 650Hp and 570 ft lbs. But we has also taken 351W and bored and stroked to a 427 and made the engines redline at about 9,500 rpm and they made about 670-700 hp but then again these are racing engines but a 408 or 393 you can find some good torque intakes and a good lift and I think you will like the outcome.
A 460 has the same stroke as a 393. The only downside to switching to a 460 is any little things required to physically install the engine and make it run with the right tranny and driveshaft length.
Could start off with a bone stock 460 and put that in and see how you like it.
I'd say you could get the shortblock done with a 393 for under $1500. Give or take depending on what actual parts you buy and what labor is required. I think the cheapest possible way is to get a 400M crank reground, use your stock 351 rods, and pickup some 302 pistons. If you can find pistons from an 88-92.5 5.0HO mustang you'd find that they are forged aluminum.
The only concern with trying to use a stock 302 piston is the bore diameter, the resulting compression ratio, and the valve clearance.
My 302 pistons in my 393 are forged from Probe Industries. They are one of the best pistons you could buy. They have valve reliefs cut in them to accept a 2.02 intake valve and have a 15cc dish for compression. You might not be able to go up to a 2.02 intake valve if you run stock 302 pistons. Also, you couldn't use stock 302 pistons if you bore the engine out .030. So you may have to get 302 pistons but they're cheap.
There are pleanty of carb intake manifolds out there for 351w's and that are cheap, 2-300 bucks. You can use a regular distributor, stock oil pump (but use hardened pump driveshaft). Find some cheap headers off ebay or swap meet...
You can get a set of performance heads for $1000 or less that would work for your engine. So with a $1500 shortblock and $1500 for heads/intake....you're looking at the rest as being small parts....could be done for about $3000-$4000 give or take.
Gonna have to spend about $100 for pushrods, could reuse old lifters if you wanted with the stock cam but it wouldn't make great power...maybe toss in a mustang camshaft ($30)....
Theres all kinds of options that are available to you....you can make it work....it just depends on how hard you want to try.
A 393 is worth about 30-40ft-lbs across the board over a 351. It also will make a flatter tq curve...which means an increase in average tq and more torque across the RPM band. However, a 351 will still make pleanty of torque and will save you about $400 on the shortblock end of things depending on what you do.
A 393 will demand that few extra for the shortblock, and demand larger heads...which increase the cost.
A 351 with GT-40Y or X style heads would make pleanty of power...probably 350hp+
A 393 will demand that few extra for the shortblock, and demand larger heads...which increase the cost.
A 351 with GT-40Y or X style heads would make pleanty of power...probably 350hp+
You don't HAVE to go larger on the heads, sure it'd be nice to, but it's not manditory. Smaller heads will simply keep the power band lower on the rpm scale. Port the E7's just on the exhaust side and use on a 393 short block. With a rv type cam you'll still get more torque than just rebuilding a 351. I built the short block for my 331 for $1500, that's really about the same price any short block will run. You really don't need a drag strip motor in a 4wd drive to tow with anyway. `
It's manditory in the sense that....stock heads will choke the ##^#$^$ out of three hundred and ninty three cubic inches.....porting them is useless....you can buy aftermarket ones for the cost of the porting.
I just ported a set of E7's in my shop Sunday. It doesn't cost that much to port a set yourself.. And yea, an E7 headed 393 ain't gonna be a drag strip terror, but it's not going to be a dog either. There are no set rules as to what you can and can't do in engine building when it comes to different displacements, heads, cams, etc. I think it ought to be an interesting experiment. I can guarantee it to work, like I said it'll just keep the powerband lower. A set of Iron GT40's would be better, but ported E7's will do just fine.
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