Quote:

I built a 408 using an eagle 4" cast crank, eagle H beams and SRP forged slugs. It was supplied as an internally balanced rotating assembly. When I received it I noticed it only needed minor drilling to internally balance, no mallory at all. It seemed odd to me and I contacted the shop and there is apparently some misinformation with eagle's specs on their cranks.

I put a neutral balance SFI damper on front and a neutral flexplate/converter combo and it ran great. Ran 11.90s in my F.A.S.T. Duster while the big motor was being built.



X1 and ditto - Check half way down -

Eagle crankshafts

Choose "Chrysler" and then "360" - it lists options for the 360 cast crank (external) and the 4" (Internal)

The Eagle site clearly states that the 4" cast Eagle is set up for INTERNAL balancing.

If you try to externally balance it, you need to rip more metal from the crank than necessary.

Some suppliers get it wrong - but your builder should have checked.