I have a 350 that has been bored 20 over stock. The engine was originally matched with 20 over pistons when machine work was done. But 4 yrs and 3 people later 2 of the pistons are missing. my question is , is it possible to buy new 20 over pistons and install them into my engine? would that be ok or would i need to go with bigger pistons and machine the block to match?

 

I think the cylinders need to be rehoned so the new rings can seat. Also, make sure the new pistons and wrist pins are the same weight as the other pistons, otherwise a rebalance may be needed.

 

the block is 100% ready for rebuild. all machine work is done and it has new freeze plugs and is painted. would i have to rebalance if i went with 8 total new pistons and just kept the 6 thats left as wall ornaments?

 

You probably should do a rebalance either way, but you're good as long as all 8 pistons are within 1-2 grams of each other. If you get a new set, you should still be fine as long as each new piston is within 8-10 grams of the old one.

 

ok. so how do I rebalance?

 

Just get 2 more pistons of the same part number and weight match them to the rest.

 

ok thanks for the knowledge Aperion and fast82.