What is the acceptable balance for the piston/rod assemblies for a stock rebuild?? This is a daily driver street engine application.

Master re-build kit from machine shop that did the grinding. Cast 366NP pistons .030 over, steel crank, RV cam. Got the hardware home and decide to check some weights. There is 32 grams difference from lightest to heaviest. The rings and bearing are dead on. I found 12 grams diff in the caps from the light to the heavy.

Should I run with it?, grind on the big ends until close or I run out of metal, or go back to the shop for a balance act and risk damage to the pistions and pins during dis-asssembly?

Rookie mistake I won't make again.

THanks

 

Are they numbered? If not, pair up the piston/rod assemblies and weigh them that way. You can put the lightest and heaviest on the same journal, and their difference in weight should cancel out.