if you took apart your short block and put it back together does it need to be sent out to be balanced ? or do you just put it all back together to specs ? or if i was to build an engine new from scratch using stock replacement block crank and pistons would i have to balance it then ?

 

The rotating assembly needs to be balanced if it hasnt already like if you just bought it new. But if you are using the same parts no balancing is needed.

 

so what would need to be installed on a new engine before it can be balanced ? oh something else that just popped in my head ... does a new block come with those camshaft bearings in it ?