hey guys, i've been told by my machinist that "When installing new pistons without over boring the block,there is always a chance that the rings will not seat right, and the engine may puff a little". Am i better off getting the block bored out and running over-sized pistons? Or is it fairly safe to throw some standard sized p30 pistons in? opinions would be great.........

 

Depending on how much out-of-round and taper the cylinders have, you might be able to just hone and rering. But if the cylinders are beyond it's limits, you would definitely need to bore and go with oversize pistons. So, with that in mind, pull out the dial bore gage and micrometers and measure away.....or tell your machinist to measure them.