68 dually 1 ton rear questions

[qksilver]

New to the 3/4 and 1 ton trucks.
Bamm 24 has a coil spring 4.10 eaton rear that I am going to pick up next month. Plus there is 4.10 pumkin for sale on the board.
I have a 68 C-30 with a factory dually conversion
I am piecing together a 3/4 2 wheel burb from a 1/2.
The question is, because I can't get to the 68 where it's stored, will a 3/4 eaton rear pumkin work in a 1 ton dually rear?
Plus what gear ratio's were available? The 68 has something like 5.17 or higher, I want 4.10 in it and the burb I would like to run something lower than 4.10.
I like that the pumkins unbolt like a ford 9 inch rears, so I would rather swap that than the ring and pinion.
Any help would be greatly apreciated...........
Thanks,
Steve