Quote Originally Posted by matt5112 View Post
CC's are both 64 cc.

The only difference in the bottom end are the rods, pistons, pins, balancer, flexplate, and cam gear.



You cannot check compression ratio short of boroscoping both types of blocks or CC'ing the pistons.

The cam gear in a N/A block is 1* advanced. Not exactly detectable.

Compression test values are quite a useless figure considering ring wear and valve/seat wear would negate any differences.



Closing the gap isn't the best way to solve this.

Have a known good ICM you can swap in?

When I first top swapped my car wouldnt run KR free past 2 psi until I swapped out the ICM for another unit.
Hmm. This argument has come up before. I think that 2 engines with the same exact cam profile and 12% difference in compression ratio would create pressures that are noticeably different, especially at cranking speed. I understand that that the NA cam is degreed differently (only 1% as you say) but the lobe separation is exactly the same...no? If the rings are bad enough to negate the pressure differences then the motor will probably need rebuilt anyway. Then you'll surely see what rods and pistons are in there.

BTW
CC'ing the cylinders at BDC is not that hard and may be an option for you.

Matt5112
I understand that you are probably much more experienced than I and if I'm wrong go ahead and beat me up. I'm learning like everyone else here.