performance question
 

Right now I'm running a 350 w/ TH350 and a Dana 60 w/373 gears in my 72 c20 w/leaf springs. I'm thinking of swapping out the rear with a newer 1-ton dually rear w/ 4.10 gears. What should I expect for changes in performance such as gas milage, torque, RPM on the highway, etc. Any info would be appriciated.

I'm interested in how you are going to do this swap as the frame is too wide for a regular dual axle (Normally)
What axle do you have that will fit?

As far as performance, You will obviously spin the squirells faster. What size tires are you going to be running? How are you handling the different brakes?

------------------
Scrub
70 GMC 1,000,000 + miles
72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.