OK, I've not been so confused since 9th grade algebra class. I need help to determine compression ratio and DCR to choose the right cam.

There are certain unknows about my block that I'm guessing at. I'm assuming the block has not been decked and the pistons are cast with valve reliefs. Here are the know specs:

350 SBC
.055 deck (if not decked?)
.041 head gasket
4.166 gasket bore
4.030 bore
3.48 stroke
5.7 rod length
64 CC chamber (vortec iron heads)


Cam: Comp Cams XE274H
274 intake, 286 exhaust
230/236 @.050"
487 /490 1.5 ratio
110 LS
31 btdc IO
63 btdc IC
77 btdc EO
29 btdc EC
Installed on CL of 106

What the CR and DCR for this combo?

Thanks!

I get 9.31 SCR and 7.55 DCR. This is using .045" deck clearance, with cast pistons (.020 short) and .025 stock deck. I used 6cc for the pistons and 63cc for Vortecs since, I hear, a lot of them measure at 62cc and others measure 64cc. With .055" deck clearance, 9.11 SCR, 7.4 DCR.

Thanks Pat, I appreciate the quick response! Based on that information I think the Comp Cams XE274H cam will work fine. Now I'll tear into that motor and find out if my assumptions are correct.. :rolleyes: