[mr48chev]

I'm pretty sure he is also doing a trans Change so that is out.

Pvienneau I forget what engine and transmission you plan to run in the truck. That might help with a suggestion on what rear to put in it.

Also what lug bolt pattern do you plan for front and rear? Life gets easier if you find a rear end with a bolt pattern that matches the front bolt pattern and pick one with a gear ratio that works with your engine and rear tire size to give you respectable highway speed and a reasonable shot at some gas mileage. That is unless you are planning a drag truck or autocross truck or have other plans rather than getting out on the open road and making some miles with a big smile on your face.

The better and more complete the info you provide is the better we can help come up with a viable option.

On six lug rears GMC had leaf springs on most trucks though the sixties and I think the change from a reasonably not so wide rear to the wider rear was between 68 and 69. The Chevs in those years had coil springs and a big old ugly bracket on the rear axle.

Those mid 70's rears along with being quite wide also have a five on five bolt pattern.