new cam profile

[rjs67]

I put together a sbc 396, 4.030 bore 3.875 stroke and 6" rod flat top pistons with plasma molly rings AFR210 race head 208/160 valves 66cc 11.01 compression. I ordered a custom cam from comp their tech helped me on it. When ordering i asked if it was to much lift he assured me it was not, I would like less lift. (1) for less valve train stress and (2) I want to use a thinner head gasket with the lift and head gasket im loosing compression I think. That's why im hear to get help. the cam specs are small base circle, lift in676 ex653 with a valve adj @.016in and .018ex, duration @.050 is in268 ex274 lobe separation is 108 i can give valve timing if needed. With a 1.52 rocker my lift at the valve is 718in and 693ex. I like the duration but think the lift should be around 600in 620ex. this is in a 3300lb car currently has a 700r4 with 9.5" converter 3200 stahl 4.11 gear and 28" tire its a spinner @4000ft elevation it has a best run of 11.60 119mph as i said spinning. I think it has a 11.30 if it will hook, and i am putting in a th350, converter will depend on the cam of course, rambling here does any one have a suggestion for a new cam thanks for any help

[iwannagofaster]

Well, we need to get the duration up, but not that high. where are you getting those numbers for the lift? .002 of rocker ratio will not give you more than about .010" lift. All of our small block lift figures are calculated with a 1.50, so a 1.52 wouldn't gain much lift at all. I would personally like to see you right around the 254/262 range with .630/.630 (.638/.638 with a 1.52) lift on a 110. That would get rid of some tire spinning torque and will keep all the mid range and top end power.

[rjs67]

the lift #'s are lift at the valve. After talking to the engine builder with the cam lift, pushrod length (8.150) and timing this is actual lift which according to him called for a spring change. also this is a foot break car no trans break and im using a M/T drag radial, the current set up (except motor) was originally with a ZZ4 the heads had been angle milled .020 the comp ex282 hr cam duration 230in 236ex 510in and 520ex lift 110ls with 1.6 rockers and performer rpm airgap this was a good set up, 12.55 @107 mph. The 700r4 will go and a th350 is replacing it but still a foot break car and I'll use a slick in place of the drag radial and of course some suspension work so i would prefer the TQ to help get it going. with the 110 lobe separation wouldn't this spread my power out a bit in the rpm range and create more low end torque? Thanks for info so far

[iwannagofaster]

That is absolutely correct, the 110 would create more torque and would broaden the power band. You have enough cubic inches to make great torque with the cam I recommended and should have a nice gain through the 1/4 mile.

[rjs67]

do you have a grind # for that cam and can you give me an any idea of hp and tq using a vic jr with 1" carb spacer and holley hp850 1 3/4" headers, thanks for the help

[amick]

The part number for the cam iwannagofaster suggested would be 12-000-9 with a grind number CS 4009/4015R110. You may need to ask for this cam to be ground on a .900 base circle if you need a small base cam to clear your rods.