Differential Swap

[Oldcar_Mechanic]

I have a 69 Cutlas with the W-31 Option and it has a 433 gear in the differential. I'm looking to put something a little more useful to the highway. At 50 miles per hour my tach is at 4700 R.P.M.'s

I'd like to swap it out, drum to drum and save this original one.

Does anyone know of any other differentials that may work other then Olds?
What would be a good gear to look for? 373? 308?

I can get a 273 but it might be to small and really hurt my performance.

Thanks for any help
Ron

[DoubleNickle]

I have done a similar swap on a GM A body. Removed a 273 in a Lemans and put in a 12 bolt 373 in for a Chevelle. Lemans, Chevelle, and Cutlass will interchane.

You should be able to look for 308s and 373s from a 68-72 Chevelle or Pontiac Lemans.

The rear end will direct bolt to your frame with no modifications.

Good luck