1971 GMC C2500 rear end questions

[Mike C]

My 70 GMC big block truck had the 3.54 geared Dana 60 and I ran 265 75 16 tires and it was pretty good combo for the road.

Expect to pay $250 for a set of gears, another $150 for bearings, and $400 at least for labor to set up a diff. Figure anywhere from $500-$900 depending on what you want for a traction device.

Obviously, you can save money buying used if you can find the right combo in the time frame you need.

Most likely a later model semi-float 14 bolt will have a Gov-Lock limited slip installed. While not my first choice, I am still running it in both the swaps I’ve done. And the 9.5” version appears to be much more robust than the 8.5” “Gov-Bomb”. Depending on your abilities, the later axle can be done fairly inexpensively.

[Baime]

Originally Posted by Mike C

My 70 GMC big block truck had the 3.54 geared Dana 60 and I ran 265 75 16 tires and it was pretty good combo for the road.

Expect to pay $250 for a set of gears, another $150 for bearings, and $400 at least for labor to set up a diff. Figure anywhere from $500-$900 depending on what you want for a traction device.

Obviously, you can save money buying used if you can find the right combo in the time frame you need.

Most likely a later model semi-float 14 bolt will have a Gov-Lock limited slip installed. While not my first choice, I am still running it in both the swaps I’ve done. And the 9.5” version appears to be much more robust than the 8.5” “Gov-Bomb”. Depending on your abilities, the later axle can be done fairly inexpensively.

Mike,
Thanks for explaining the costs involved. If I had a semi-float 14 bolt, would those costs be drastically lower?

My plans keep changing as I get more information from this group. I appreciate the shared knowledge. I'm very much a rookie regarding GM trucks, but I'm willing to learn.

I have some decisions to make. Based on all of these comments, I believe my best options are:
1) Leave the Dana 60 with 4:11 gears alone, and change over to a four speed transmission with overdrive. (T700R4, or 2004R?)
2) Update my existing Dana 60 rear end with the 3:54 gears (preferable with positraction), and stay with the T350 three speed transmission.

A comment: If the Dana 60 is a decent rear end with available parts, it doesn't seem to make sense to change out the whole rear end to a semi-float 14 bolt.

Take care,
JP