2x4 and 4x4 frame ?

[jcueckert13]

I have a 1970 GMC c10 lwb stepside that is 2wd and at this point it is sitting in the front yard with no motor and is used for parts storage, i also have the frame to a 1971 4x4 suburban sitting 20 miles away with the front axel, springs, mounts and steering linkage that due to mud i cant go look at right now. what i am wondering is what diference is there between front half of the frames? I am wanting turn the gmc into a 4x4 and looking at the front end all of the 2wd parts just bolt on so i am guessing it would be possible to just bolt on the 4x4 parts and with a new trans be able to have a 4x4 truck.

[1969k10stepside]

Dont know about the front really but the rear will be different if it has trailing arms which the 4x4 wont. The motor sits back further on the 4x4 also.

[jcueckert13]

both are rear leaf springs, the gmc has the hd option for the rearend

[qksilver]

A lot of it will bolt in because the holes are already there, the rest you would have to drill and use grade 8 bolts instead of what the factory did(rivets)
It will work.
I have been looking for a swb 4x4 frame for a while.
The 2 wheel leaf spring frames have the same bend for mounting coils. They will interchange but aren't the same but will work

[jcueckert13]

well i guess ill tow the burb frame home and start piecing the 4x4 parts together under the gmc, i figured gm would have been too cheap to make 2 completly different frames for 2wd and 4wd.

[GMCMAX]

You also need the high hump floor cab as far as I know.
I converted my 68 GMC to 4X4 without swapping the frame. I used parts from a 70 blazer for a donor. I learned a lot about frame differences. I was lucky when I bought the parts that I got most every thing I needed from the blazer like the front crossmember and motor stands. I had to flatten out the big dimples in the front of the frame where the e-brake line comes through to install the rear mount for the front springs. The front front hangers are riveted to the core support mounts on 4X4, I knocked off the 2wd core mounts and bolted the 4X4 spring hanger/core mounts in. From there just measured the spring length and set the rear mounts accordingly. The rear end spring hangers are shorter, and I had to put 4" blocks in the rear to get it level with the stock blazer front suspension. Rivets are a pain to remove, but after nicking the frame with the torch, I drilled through them with a small bit, then took a larger 3/8"? bit and drilled to cut the head off then used an air punch to knock the other part out.
Took about two weeks in the winter, but it was well worth it.

[67chevytodd]

What about 4x4 parts from a newer (78") Blazer? I'am considering a similar project with a 72 short step, but my donor is a 78 chevy Blazer. I know the rear suspension is different, but has anyone ever tackled this swap? Thanks Todd.

[jcueckert13]

i just got back from looking at the remains of the suburban and my dad suggested i swap the gmc body over to the subrban frame and make a extended rear bumper, i havent decided yet but the swap looks fairly straight forward. i will probably be towing the carcas home next sunday and it will be a few months before i start the swap.

[Mudder]

I would just shorten the burb frame and use it. It's not hard to shorten a frame if you can use a square, torch and welder.

A 78 Blazer frame can be used but will have to be lengthened to work.