According to the info I have a 270 Jimmy has a bore of 3.781 while a Chevy 292 has a bore of 3.875. With an overbore of .090 on yours to clean it up your now at 3.871 so you'd need 292 jugs +.030 for a 3.935 bore. So my question is can you bore a 270 by .154? Man, that seems like a lot to me. Most 292 will accept a .125 bore but even that gets the wall pretty thin. Seems scary to me but I'm sure you have figured all this out. Wouldn't you be better off to find some overbore 270 pistons? I don't know what 270 pistons look like but stock 292's have a large dish depression in them to lower compression so that might be a problem too. Call me a worrywart I guess. Am I missing something here?
