engine bore

Does in make much difference boring our engines 20 over or 30 over. I know from stock its a improvement but let's say between .020 to.030 it there that much improvement or is it easier to find pistons.

I had no problem getting pistons for my rebuild. My block is bored .20 over, so the pistons were 50mm oversize. Just make sure your parts supplier knows what size your getting. You will also need to get the same size piston rings to match the pistons. As far as power gains.... I'm not sure what they are. I would imagine they are fairly minuscule.

According to DD going .030 over greatly expands your piston ring options and makes better rings available over the .020 overbore.

We built an SC engine that was .040 over....

Customer has ecstatic with the overall performance of that engine....

Or maybe it was because we ported the exhaust manifolds.....