So if I buy the 3:55 gears for $350 and the installation kit for ?, what would it cost to have them installed by a shop? Am I going to hahave $1000 in this upgrade or ?
Replacing the gears in your existing torque tube rear end is the most economical way to go.
If you do not have ability to install the gears on your own.... Whatever you pay someone to do it is between you & the installer.
This 3.55:1 gear swap is pretty cheap if you consider the alternative.
Alternative:
Locate a complete used newer axle with highway gears from a newer model truck.
Cut off the spring mounting pads & fabricate new mounting pads & weld them on.
Replace the original closed driveline transmission with a trans. that has an open U joint.
Have a driveshaft made from scratch to fit & replace both U joints.
Rebuild the brakes on the used rear end as they are no doubt worn {hopefully you won't have the replace the brake drums when you do that}.
Try to figure out a way to get the later model brakes to handshake with your original braking system.
Try to figure out a way to get your original parking brake cables to work on the new rear end.
And... after you go thru the trouble of doing all that.... the new {used} rear end may last 20 years or it may last 20 minutes.
Chris Sweet already went out of his way to post an excellent tech article on installing the highway gears in your existing torque tube rear end.
http://www.stovebolt.com/techtips/axles/355%20gear%20swap/.
