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

Duster346 said
The thrust washers are the same material for aluminum or steel planetaries, but the thrust washers themselves are different and do not interchange between the 904 aluminum and steel planetaries.

Do you have aluminum or steel planetaries?

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