Rod Crank Balance Questions

[yellow1]

Ok, This is not a small block I need help on but there is not a big block question heading. I am doing a somewhat budget build on a late 70,s 440. Engine first had a cast crank with LY rods, externaly balanced. Found a Forged 440 Crank that I would rather run instead(of course). Yes I have the harmonic balancer for the forged crank, but this forged crank had the 6 pak or heavier rods in it. Question is am I going to have to get all of it balanced which means taking pistons back off of the rods ( which is risky). Anyone else ever gone thru this?

 

[Mopar367]

Yes you need to have your rotating assembly balanced when mis-matching parts like that. If your pistons and rods from the cast crank assembly are being used, they are a different weight than the 6 pack rods and pistons you say were used with the forged crank. The bob weight of the crank is what balances it. Just hope if you get it balanced they don't have to add material as it can get expensive.