Need to be balanced?

The pistons are weight matched, not balanced and the rods are balanced but the problem arises when you put much lighter pistons and rods on a crank that was originally balanced for heavy parts. That throws the bob weight way off which is why it is imperative you have it balanced. If the engine is for perf. use I even have stock stuff balanced cause the factory balance job was marginal at best.

You will need your balancer, flexplate and converter to get it balanced. Actually the best way for you to do it is since you have none of those parts is to buy the B&M 360 external balance plate (part #10236 for a 727 trans. and part #10239 for a 904 trans.) then you can use a neutral balance torque converter and you don't need a converter to have the assy. balanced.