Differences in GMC and Chevy Frames?

[HOTRODJOHN]

I am trying to find out the difference in the GMC & CHEVY frame. I know that the GMC has a leaf spring rear but are the front suspensions the same and the other body parts interchangeable. I want to shorten the frame to make it a short bed and trying to figure out if the articles I see on how to do it close enough or should I figure something out myself. Thanks, John

[Ed Snyder]

Originally Posted by HOTRODJOHN

I am trying to find out the difference in the GMC & CHEVY frame. I know that the GMC has a leaf spring rear but are the front suspensions the same and the other body parts interchangeable. I want to shorten the frame to make it a short bed and trying to figure out if the articles I see on how to do it close enough or should I figure something out myself. Thanks, John

When I did the "restoration" (or "restomod" or whatever you want to call it) on the green '66 you can see in my avatar, John, I had the long bed frame shortened to be able to put a short bed on it. If you're wondering if a Chevy short bed will fit on a GMC frame, it definitely will because that's what I did. I had the first cut made straight down from the back of the cab and the second cut made 12" to the rear. The joined sections were reinforced with "fish plates". Another 8" was cut off the tail ends of the frame rails. Then the Chevy short bed bolted right on using existing holes in the GMC frame. Hope this helps!

[HOTRODJOHN]

So I so not have to remove the cab and move the cab mount. I looked at it and cannot figure out why I saw an article where they cut it under the cab and then moved the mount. Saw no reason why it was do that way. Thanks for the info. I will post photos when done.

[Ed Snyder]

Originally Posted by HOTRODJOHN

So I so not have to remove the cab and move the cab mount. I looked at it and cannot figure out why I saw an article where they cut it under the cab and then moved the mount. Saw no reason why it was do that way. Thanks for the info. I will post photos when done.

There's definitely no need to remove the cab nor move the cab mount, John. The cab on my '66 (now owned by Clyde in SC) was never off the frame. Good luck with your project!

[HOTRODJOHN]

Thanks, for you most informative information. Truly is a time saver. John

[Ed Snyder]

Originally Posted by HOTRODJOHN

Thanks, for you most informative information. Truly is a time saver. John

It should go without saying, though, that you should check the dimensions on the frame and bed you're working with before making any cuts to confirm that what I did works for you as well.

[bpmcgee]

I don't have my book in front of me, but didn't leaf-spring trucks and coil-spring trucks have different frames?

I know the coil spring trucks have an X frame. Didn't leaf-spring trucks have a ladder frame?

B

[HOTRODJOHN]

I am not sure about the ladder bar suspension. But I am going to someone's house this weekend who has a Chevy frame and I will check. It is a bare short bed frame. Figures after I do the work I find a frame. I am going to buy it just to have it if I ever need it, John

[bpmcgee]

I just got my book out, and I was correct. 4wd (leaf spring) trucks had ladder-bar suspensions while 2wd (coil spring) trucks had x-frame.

B

[David R Leifheit]

Originally Posted by bpmcgee

I just got my book out, and I was correct. 4wd (leaf spring) trucks had ladder-bar suspensions while 2wd (coil spring) trucks had x-frame.

B

Differs by year though.
Torsion bar front/coil rear are early (1960-1962)
coil front/leaf rear are later (1963-1966)

4 wheel drive is another (3rd) frame type.

From the club page:
http://6066gmcguy.com/GMCvsChevy.html

GMC:
1960-62:
Torsion Bar Front, Most all Models
Coil Spring Trailing Arm Rear - 1000, 1500
Leaf Spring Rear - 2500 & Larger
1963-66:
Coil Spring Front, 1000, 1500 & 2500
I-Beam Front Axle - 3500 & Larger
Leaf Spring Rear - All Models
Some Larger Trucks had Air Ride Springs.

Chevrolet:
1960-62:
Torsion Bar Front, Most all Models
Coil Spring Trailing Arm Rear - 10, 20
Leaf Spring Rear - 30 & Larger
1963-66:
Coil Spring Front, 10, 20 & 30
Coil Spring Trailing Arm Rear - 10, 20
I-Beam Front Axle - 50 & Larger
Leaf Spring Rear - 30 & Larger