Right on, thanks Streak. I don't know if I have said this yet, and right now I dont feel like going back to look, but... I am going to be using a Flex-a-Lite 3 core radiator with dual puller fans that move about 4,000 cfm, as well as an oil cooler, power steering cooler, and maybe a fuel cooler. The power steering cooler is going on there because I am going to be using a hydraulic winch, and I really don't like replacing PS pumps. The fuel cooler is partially so I can say I have one lol, but also because I am going to be running an in bed 22 gal fuel cell, and it just seems like a smart thing to do. Now, this is one question concerning camshafts that has been bothering me for a few days. All the numbers that are listed for the 300 are at factory rocker arm ratio, which is 1.6 to 1. If I get 1.7:1 rocker arms, then the valves are going to open more, I know that, but I don't know how to figure out how much more. All the stuff we do concerning diesel engines you don't deal with anything but rocker to valve stem clearance, plus you don't put different cams in OTR diesel trucks. What I am worried about is if I get taller pistons, and a bigger cam, will my valves clear the pistons with either stock or higher ratio rocker arms? I know how to check for that, with the clay and barring the engine over, but I wish I could find a spec sheet that has all this info on it. Does anybody happen to have valve clearance #s and etc?

 

AFAIK there isn't an existing list of cam specs that work because in stock and mildly built applications there is really no danger of clearance problems. Most stock pistons have a very large dish in them, as much as 0.300" deep. When the piston is at TDC and the cam is in split overlap the valves are open less than 0.1" even with decent sized cams. That isn't enough lift to get the valves out of the combustion chamber, never mind anywhere near the piston. With a large cam and a flat top piston running at a performance oriented deck clearance you are liable to run into problems. This is another good reason not to mill the head to increase compression. Every thousanth you mill the head moves the valves a thousandth closer to the pistons and requires a deeper valve relief. A true flat top with an EFI head will give you around 11:1 compression. With enough cam you will be able to run that on pump premium, but that's a lot of cam with a 50 ci cylinder. Probably around 300 degrees on the seats and around 230-240 degrees@0.050". The LCA is going to be tight, maybe in the 108 degree range. That's going to give you about 10-15 degrees around TDC during overlap that both valves are off their seats 0.050 or more. 0.050 doesn't sound like much, but if the head is milled a little bit things can get tight in a hurry. Think about it. Most serious engines now days are running a negative deck clearance to improve quench, lets say -0.010. With a 0.038" head gasket there will only be 0.028" between the head and piston at TDC. Typical valve to piston clearances are 0.080 for intake and 0.100 for exhaust. That means the valve can't be closer than 0.052 to the bottom of the chamber at split overlap. You could spread the LCA out to get the exhaust valve closed sooner, but it will hurt power. The exhaust valve is where you really need to focus your research in this area. Most piston to valve contact happens on the exhaust valve because the piston is chasing it up the bore while it is closing. With duration numbers like the ones above (240 @ 0.050, 108 LCA) the valve will be at it's peak lift (we'll say 0.550) at roughly 108 degrees BTDC and will drop to 0.050 at 12 ATDC. If we assume that the lowest part of the valve is even with the chamber when it is seated we can make a good guess if there will be problems. If we assume the lift is linear we know about how far the valve is open for any crank position, but in the real world it opens faster at low lifts and slower at high lifts. That is important because it means our estimate might be too tight as the valve closes, but the valve doesn't open straight down so it might still clear. At 20 BTDC the piston will be (using stock dimensions) about 0.180" down the hole. The valve at this point will be open about 0.090 giving us a clearance of 0.090. That's under the 0.100 needed. At 10 BTDC the piston is only 0.030 down the hole and the valve is open 0.068". BANG. Even considering an 18 degree valve angle it would still hit. Somebody check my math because I'm tired and probably missed something. The point is that the piston is headed north faster than the exhaust valve and you will either need to figure all this out before buying a cam and pistons or have the measurements available for the cam and piston company you choose.

Running a 1.7 rocker instead of a 1.6 will increase lift about about 6.2%.

 

i have stock cam specs if u'd like...i have lots of stuff about teh 300 no one else really has ;-)

 

get me them specs in email at broke77f100@aol.com i would like any and all specs if u have them

 

great info there Streak. I really appriciate all the help. That kind of information is going to either make or break this project. Optikal, why not just post what info you have here, where everybody can use it? Again, thanks for all the help guys. Hey, in my never ending research into vehicles and how they are set up, I happened to stumble upon the old Mopar 6 pack carb setups, and thought about running something similar with the Clifford dual plan intake manifold and a couple Holley 390s. If you don't know what I mean, they used to have 3 2 barrel carbs on a tripple plane intake manifold, and a sequential throttle linkage that allowed 2,4 or 6 carb bbls to be opened, so if you kept your foot out of it, or were on the highway, you would get good mileage. My buddies dad gets 23 mpg in a Cuda that has a 6 pack on a 383 I believe (pretty sure he did it himself). Anyhow, has anybody seen a kit for such a setup? I know I have once, somewhere...

 

there are kits for v8s, I have never seen a 6 pack or dual carb setup for a straight 6 but one good 4 barrel has been proven to outperform 3, 2 barrel carbs, mainly because of runner length and intake design. As far as gas mileage goes, if you keep you foot out of the throttle, you will be running on 2 barrels with either a 4 barrel or a "6 pack" set up. however if you were running on 2 four barrels with the same linkage to both, you would have to lean out the primaries because you would be running on four barrels all of the time. Of course you could make the second carb come in with the secondaries of the first carb. I am not an expert but I would say that since the 300 only has 6 intake valves a good 750 cfm carb would be your best bet for the power you want.

 

yea but dual 390s is 780 right? thats 30 cfm more..what could it possibly hurt to add more air? and my plan is also the dual quad intake with 390s or the triple side draught webers...which would make more power?

 

its just harder to set up and tune, but if thats what you want to do go for it. if power is what you are looking for broke77, any one of them is a good choice but only having to tune one carb is just that much easier in my opinion.

 

I have seen three deuce intakes for a 300. Im pretty sure either offy or holman and moody made it. Either one sounds possible but Im pretty sure they would be old production and not something made now sitting on the shelf. Clifford has 2x4 intakes and webber side draught intakes on their website. If you put one mechanical secondary and one vaccuum secondary carb on a 2x4 intake and run the mech. one in the rear and vac. in front you will mostly be running a 2bbl carb unless you are on the gas. I did this on my Boss 302 but I will say that 2 450cfm carbs were still way too much fuel dumping in on the motor. I know 450 is bigger than 390 but also remember the valve size of a boss/cleveland head and the nature of the motor itself is at the other end of the spectrum from a 300, wild or not. Just my .02 in a totally non negative way

 

I honestly think the webers are just a money making scheme honestly. By the time you buy the intake and all three carbs, plus have someone tune them for you because you are too fed up to do it, you will probably be into the setup about $900, or at least thats the way I have it figured. I noticed it says you have to use manual chokes on the dual plane setup, so forget that idea. more later, time to eat.

 

my truck has a manual choke on its 1bbl carb...its really not that difficult to use...just pull the **** and start it

 

yeah, but what about cold start conditions and etc? These are the 2 carbs I am looking at right now... http://store.summitracing.com/compar...s=P%5FRank%7C0
I'm leaning towards the Holley. BTW, on the Edelbrock EnduraShine products like the aluminum intake manifold, what are they, chrome plated? If so, I think I may just get my intake manifold chrome plated. That would look soo bad, not to mention it might smooth out the airflow. I think I may just go single carb, seems easier and cheaper to me. Anyhow, I'm out of here for tonight, talk to y'all tomorrow.

 

well Holley is probably the most popular and one of if not the best carb man. out there...chrome plating would look pretty sick...but make sure your header is ceramic coated to reduce intake heat...

 

if im thinking correctly it would only take me 500 HP to get my 77 F100 to 12 sec 1/4 times...that is with traction permitting...so 600 HP would def. get me 12s but i could make the best and go for 11s?

 

oh and thats at around 125mph