Originally Posted By Moparteacher
Where are you going to find a .010" over piston? Or, any 440 piston that doesn't start at .030" over? Custom? It's likely to cost more than a shelf piston. And what about rings for a 4.330 bore? They're available but I only see 5/64, 5/64, 3/16 oil.

A replacement std piston is the same cost as a .030" over piston, and the machine work is likely to cost the same whether .010" over or .030" over. Plus a quality piston in std is more difficult to acquire than a .030" over piston. Most manufacturers don't offer std. pistons anymore.

Measure the taper in the bore. It may come round and straight with a good power hone with just a few thousandths taken off. Then run a forged piston a little loose with file-to fit oversized std rings.

So lets say is needs .005 to get straight and round 4.325". A forged piston is likely to have .003" clearance machined into it at 4.317". You now have .008" clearance and it's still a std. bore. No boring bar needed, just a hone.



I would like to bore not more than needed to have as much wall thickness as possible. Racetec/Autotec pistons are available in custome sizes so the .010 over shouldn't be a problem. The rings seem to be the real problem at the moment as I coulnd't find any 010 over rings in 1/16"