Reply to "Rich K's New Engine"

Hi Rich

My understanding of your application is a "351c 4v flat top pistons quench camber heads automatic trans". Your engine shall have about 9.5:1 compression ratio or more, depending upon the piston's compression height, the head gasket's compressed thickness, the head casting (D0AE or D1AE), the deck height (9.215 or less), and the bore diameter. It would be helpful to have a more precise number.

Cams 1 & 2 close the intake valve at 60° ABDC and are intended for an engine with less static compression than yours. Your engine will need a camshaft that closes the intake valve around 70° ABDC; with a more precise figure for the engine's static compression I can be more precise in helping you.

I know you've been unhappy with past choices in camshaft, I assume you're looking for better drivability? Your current Lunati cam (hydraulic flat tappet) has the following specs:

275°/290° duration at 0.006 (advertised)
225°/240° duration at 0.050
0.550/0.560 gross valve lift
110° LSA
106° ICL
_____________________________________
Seated valve events @ 0.006
EVO = 79° BBDC
IVO = 31.5° BTDC
Overlap = 62.5°
EVC = 31° ATDC
IVC = 63.5° ABDC

That IVC would work with 9.6:1 static compression or less

The amount of overlap and the intake valve opening (IVO) dictate drivability. I think you'll be happiest with a camshaft having 55° overlap or less. You'll also be happier with 114° LSA than 110° LSA. And because the engine has 4V heads it needs a dual plane intake manifold with a full height plenum divider.

I could use two bits of information from you, (1) a more accurate number for the static compression, and (2) what rev limit have you set the engine for, 6200 rpm or 7200 rpm?