I have a 1971 429 block that was internally balanced. I could not reuse the crank in the rebuild so I have a post '79 crank from a 460 with a casting of 3YA which is externally balanced. Can I have that crank internally balanced to use in my build? I did not get the flex plate with the 460 crank and was going to reuse the flex plate from my original crank. Is this doable? Can I externally balance, (not what I want to do), using an aftermarket adjustable harmonic balancer? Thanks,
Doug

 

Yes if you are going to get a ext. bal. crank rebalanced you have to take the weighted parts in with your crank.
Did they replace the clutch when they changed the motor ? If they did and it's a reman, I'd wonder about the clutch as far as the vibration goes.

 

Mark A.,


Everything I have is 1971 429 including the C6 automatic tranny that I'm rebuilding so no clutch. The only changed part is the crank. I had to go to the 460 crank due to the limited piston selection for .030 over pistons with a 3.59 stroke. The only available 429 pistons were 10.5 to 1 flat tops which I couldn't run with pump gas and D0VE-C cast iron heads. Changing to the 460 crank gave me virtually an unlimited selection to pick the compression ration I wanted for my build. I settled on a piston selection of 9.8 to 1 for my compression ration. That being said, the 460 crank available, was a post-'79, which is an externally balanced crank. I took everything to my machinist yesterday and he says he can internally balance the crank for use in my motor with the other parts, which is my preference. The dilemma was not having the externally balanced, weighted flex plate and crankshaft counter weight behind the harmonic balancer or the harmonic balancer for the 460 crank that I had. I'll have to wait and see what my machinist comes up with. Thanks for your input. I was starting to stress over this.
Doug

 

Whoops wrong thread.