'72 C20 rear end for a C10 rear end!

[turbobuick1]

I have a '72 Chevy 3/4 ton C20 truck that I'm basically looking to downgrade to half ton status. My logic behind this is-
1) I'm looking to get the 5 bolt pattern, so I can change my wheels.
2) I'm looking for more of a highway gear (around 3:42 or so). I haven't had time to research or count my gear teeth, but I'm assuming it's a 4:10 or taller.
3) I'm don't need the truck for 3/4 ton duty, and I'm hoping the half ton rear end might be lighter.
4) I'm in the process of a custom engine swap, and will need to make a custom driveshaft. I figure I should put in the rear end I want before I get the driveshaft made.

I should say I have a coil spring rear suspension. I should also say the truck has 72,000 original miles on it, and I just drove this truck from Idaho to Michigan in March, so the rear differential works flawlessly. It is still bolted up in the truck. I will post pictures soon.


And I'm still learning about these trucks, but what axle do I have? It's a Dana isn't it?