If I bore a 302cu in .30 over what will the new cubic inches be. Also approximately how much torque improvement.

 

That gives you a 306 and probably no measurable difference in power. You gain 4 CI, but you lose just a tick of compression.

Is this just a clean up bore during a rebuild?

http://www.wallaceracing.com/cid.php

 

Wouldn't boring out the cylinder GAIN a tick of compression? It's squeezing a little more volume into the same combustion chamber.

 

Bigger space and VE is not 100%. Marginal VE is even lower. Plus you usually have a bigger head gasket gap.

 

Yes, you gain compression by increasing the bore.

 

Checked a couple of static CR calculators. You are correct, you get a bit of a boost in CR with a bigger bore, all else being the same.

Dynamic compression....not sure, but given the marginal volumetric efficiency, I don't see how you gain cylinder pressure while running. I suppose there is a standard, known calculation for that as well, but I don't feel like looking it up and proving myself wrong again.

Op hasn't been back yet.....