What cam to use.

[Johnny from Chicago]

I have just bought edelbrock heads for my 383. Any idea how much piston to valve clearance I have with a zero deck and 84cc heads, 5cc relief? I'm unsure what cam to use. I have a 3000 stall in a Protrans, 4:56.1 gears,29.5x9 ET drag slicks, performer rpm with a holley 750vac sec with the block kit(will replace with better if needed). Edelbrock rpm heads with 9.1.1 uncut or 9.8 cut .040 with .039 gaskets. I want to go as fast as possible without changing any of the core parts. It's in a 70 Dart 3100lbs. I and planning on a small nitrous shot and next year I plan on a procharger P1sc. So, what cam advice do you all have.

 

[moper]

Sounds like you have a lot of plans for that engine. The only way to know for sure, is to measure it, with the cam you plan to use. I would suggest this..You will want more static compression when the enige is naturally asprirated, or running the NOS sytem. I would be aiming for 10.5-10.8:1 with the .039 gasket. For a cam, I'd go like a Crane H-302-C. It's a little bigger hydraulic, but for NOS it will run like mad. Now, I would not run this with the blower. For the blower, I'd use thicker Cometic gaskets to drop the compression to 9.5, and run a smaller cam, most likely a custom ground unit with more exh lift and duration, and less overlap. using the lower compression w/o the blower will make the engine feel sluggish down low. Using the higher compression with the blower could be trouble with detonation. My $.02..

 

[rumblefish360]

Seeing how you want to use a blower later on, it would be a chocie of cam for fast now and change later or cam for later even though you do not have a chareger on the car now.

I think a custom cam would do it well.
The amount of clearance you have can be found out by putting clay on top of the piston and start turning it over by hand.
This is the only way to find out because even if someone else has the exact cam you have now, theres could very well show different clearances.

 

[cuda66273]

You want the right cam? Call a MOPAR Cam engineer

Jim at racer Brown....410-866-7660 after 2PM EST

You need to lose that Vacuum carb, that's for your Mom's 68 Coronet Wagon.
Bolt on a 750 Mighty Demon.

Nitrous? If your going to use a Baby Bottle then forget the Felpro gaskets and get a set of Cometic Custom MLS gaskets .027 to .120 cut to specific bore size, a little more than felpros until you have to do the job over....*grin*

 

[sickt7cuda]

Your set up is very similar to the one I was running. My 383 had the original flat tops (no valve reliefs) and a .501 hydraulic cam. I added some 84cc Eddy heads, swapped out the cam to a crane solid .540/.560 lift. I trusted a friend(?) when said there was no need to clay it to check for piston to valve clearance. Guess what? It broke badly. The valves were slapping the pistons til they broke in 3 cylinders and bounced around a while until they finally settled into the valve seats - sideways. It was a very expensive lesson. Check for clearance - assume nothing - verify, then check it again.

 

[kruger]

Your set up is very similar to the one I was running. My 383 had the original flat tops (no valve reliefs) and a .501 hydraulic cam. I added some 84cc Eddy heads, swapped out the cam to a crane solid .540/.560 lift. I trusted a friend(?) when said there was no need to clay it to check for piston to valve clearance. Guess what? It broke badly. The valves were slapping the pistons til they broke in 3 cylinders and bounced around a while until they finally settled into the valve seats - sideways. It was a very expensive lesson. Check for clearance - assume nothing - verify, then check it again.

Hes right, NEVER assume in that department.. Check it twice n thrice?

 

[383man]

Yep I agree .........you better check it. We use KB flattop pistons .025 down on my sons 400 with valve reliefs in the pistons. It has the MP .557 cam and 84 cc Eddy heads we cut .040 to get 10.2 comp with the .039 head gasket. It has over .150 valve clearence but like I said it has good size valve reliefs in the flattop pistons. Ron

 

[Johnny from Chicago]

I used the compression ratio calculators and if I cut 0.40 off my eddy 84s I'll only have 9.8:1 My deck is zero and gasket .039 with 5cc reliefs .040 over 383.