Yeah, I have a $50 3.23 axle from a 4 door 83 Regal in mine coupled to a TH200 4R with the .68 OD 4th. Unfortunately, the lack of a posi means I have absolutely no traction, so it isn't any quicker off the line...🙁 With the OD and the 2.41 it was terrible on gas and accelerated poorly. The 3.23 actually improved fuel mileage because it wasn't dogging the engine so bad out of the hole and required less throttle. The 2.41/3 speed is only good --as far as fuel economy is concerned-- at a steady state highway speed but is horrible around town.