geting ready to redo my eng.and would really appricate some help. I think my cam is to big to start with,my machine shop told me this was what I needed. Hear goes a 396 now a 402 pistons 3/16 dome-.187 9.6 comp. closed 215 oval heads,1.88-2.19 ss valves. heads shaved 30. headman headers 750 carb 4-speed 331 gear. what cam would work with this? this is my cam now hydraulic lobe lift 310 exh.325 valve lift 527 exh.553 @50 int 224 exh 232. @.006 int.290 exh.292 timing int. opens@4btdc closes @34abdc exh.opens 44bbdc closes 6 btdc 99% street. please help I have a set of 049 heads ready to go if I have to change pistons Thanks Jim

Too big? The duratiopns might be a smidge big, but with the intake closing at 34 ABDC, and 9.6:1 static, you will certainly have good cylinder pressure. I would like you to download Pat Keyy's dcr calcualtor and see what the dynamic is. A high dynamic pressure will make more torque ( power ), and mitigate to some extent, the softer bottom end of that cam.

Your valve events must not be seat durations, but measured at a certain lift. In the dynamic compression program, it wants seat timing. For example, a 292 seat, 110 lsa on a 106 intake centerline, gives intake closing at 70 ABDC.

In which case the dynamic compression of the combo would be 7.25:1. OK to run 87 octane, but not for great clylinder pressure or low rpm grunt with a midly big cam.

I checked the cyl pressure cold with the plugs in and all I got was 140

I'm not sure how much more it goes up when hot, but not to the 175-180 level where you start making good power.

yeah, too big.

Any Idea on what size cam would be best? This 67 chevelle wont even spin the tires when you stomp it in first gear

Yeah, I would think. Something with seat durations in the 270range, ie.e Crane 272H10, Comp XE274, etc. Maybe even high 260 seat duration.