Just Purchased Virgin 340 Short - What to do with Pistons

New rings are not expensive. But as mentioned above, wear in the ring grooves is just as critical. If you have worn ring grooves, the rings will flex and twist constantly, and will wear out quickly. Back-in-the-day, you could reuse a set of pistons with worn ring grooves, by having the grooves machined wider and then inserting a ring spacer to take up the slack and get back to original groove width. A ring spacer looks like an oil control scraper ring. Dunno if many machine shops will do that anymore, or if they can do it economically.

Good deal on the heads; tnx for rthe info.

If the piston tops truly are .070" down in the hole, then even with these milled heads at 65 cc, and with a .039" head gasket, you are looking at around 8.0 static CR. Yep... typical smog era stuff! It'll only go up to around 8.25 with the .028" head gasket, but the heads and deck need to be good and flat to use those, per reports here of them tending to not hold at times.

So if the measurements we are discussing are right, then you sure as heck don't want to cam this thing up an use it as a cruiser.....your dynamic CR is gonna be in the toilet. Think: more sluggish than a stock smog era 318 ......ooooo-ow, that hurts to even think about LOL

Maybe it is time to PM to 512stroker on his hi-comp 340 pistons.... that is a generous-sounding offer IMHO.