The least expensive way to do this is to find a the rear axle form a 54 powerglide car. They had 3:55 gears. I don't know if you can use the whole rear or not or if the ring and pinion will fit right in your housing. I did this swap in my 37 sedan and had to use the torque tube and axle housing from the 37 and had to have the splined coupling changed where the pinion meets the inner drive shaft. You just have to play a little mix and match to get all the right parts. I think the whole job cost me about $150
Gael
