Frame rails
 

Don't have time to look for it but was wondering if 2wd 1/2 ton frame rails are the same as 4wd 3/4 ton for the 80's model.

Re: Frame rails
 

I don't think so.

There was a great post with a GM frame chart here, but I can't find it. Anyway it related GVWR and series with bending moment. There was a lot of factors, but mostly relating to section modulus, and for those series (as dimensions are basically the same for long bed rails) the thickness of the steel was the difference. There was some crossover, but very little. IE- its possible that a heavy 1/2 frame rail would be the same as a light duty 3/4 rail, but it would need to be referenced by serial number.

Re: Frame rails
 

So is that what a heavy half is? Just a beefier frame but 1/2 ton suspension? What is the Big 10?

Re: Frame rails
 

The look a like but not sure on the frame thickness if that matter or not.Why do you ask?Is your frame rotted out or trying to do a 4x4 swap by swapping the bodies?

Re: Frame rails
 

Thickness is different

Re: Frame rails
 

Actually I have a 86 roller that I am using the suspension and rear-end in my 64 and a kid at work has a 3/4 ton 4x4 that has a cracked frame

Re: Frame rails
 

Other way around.

Big 10/Heavy Half use the 1/2 ton frame but get heavier duty springs/leaf spring packs.

K