20+ years of "Building 904/727 for drag racing use"

dart_68 said

The front planetary is 2.74 steel 4 pinion. The rear is 3 pinion aluminum (stock from 1969 but in good shape).

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I always wanted to use an aluminum 3 planet for weight savings but was never sure if it’s strong enough and I use the rear 4 planet steel from a 998 or 999.