From what I can tell in the factory service manual, you have a full floating axle. I'm assuming it's the same as the later HO52's. In that case, you'll have the 4.57 gearset and the best you'll be able to come up with is a 4.11 set from the 68-72 trucks.

http://chevy.oldcarmanualproject.com/chevyresto/4670.htm


1954 3600 Chevy Truck
"The Fake Truck"
In the Stovebolt Gallery
More pix on Photobucket