1951 Chevy 3800 Dually Chassis Swap- Frame Shortening

Before we jump into the specifics of what we’re doing here, I’ll give a brief introduction of the project (full project build thread will soon be linked here).

Current truck above and rendering of what it’s going to look like below.

For the purpose of this post, however, I’l just say that we’re swapping the body of the 1951 Chevy 3800 truck onto the chassis of an 1982 GM 1 ton dually which will require taking 23″ out of the wheelbase. We’re doing it so that we can match the original 137″ wheelbase of the 3800 truck. “Why would we do this?”, you ask? For 3 reasons.

The goal is to be able to use the truck again as a truck, so we wanted to have as beefy of running as original (No s-10 chassis swap here) as we want to be able to haul and tow with this truck.

We wanted disc brakes, power steering, and a rear gear that allowed traveling at highway speeds

Cost- To accomplish the above on the original frame would be much more costly than swapping the body onto a chassis that already got us there.

Now that you know why, lets talk about what we did.

Ok, we cut the frame in half… with a saws-all…. then welded it back together. Pretty straight forward. Well, it was a bit more than that. Instead of making straight cuts, we measured, marked, and measured again, and cut out a “Z” shape so that when it went back together, it would be much stronger than just loping off the frame straight down.

Original 1982 1 Ton Dually Frame

Time to cut!

After doing this to both sides, we pushed the back half forward 23″ to join back up with the front. Fingers crossed our measurements were close.

Good enough!

Now, to clean up the cuts, line everything up, and glue this thing back together!

It welded up nicely. Now to grind down the welds and smooth everything out.

After a quick coat of paint to cover up the bare metal, you can’t even tell we were in there!

Don’t worry, we’ll be boxing the inside as well for some added strength, but it came out pretty nice and will be plenty strong. Because the truck will have a flatbed on the back, there wasn’t any need to worry about any bed mounting locations lining up.

More to come as we fab up the body mounts and start to get the rest of it together!

Stay tuned!


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  • Matt 2 years ago

    If you used 19.5 inch 8 lug chev wheels , would that size of wheel work without hitting the brake caliper ?

    • Nick Matt 2 years ago

      Hey Matt, the caliper clearance has more to do with what wheels you’re talking about than just the size. In my case, 18” wheels where stock. So, the 19.5” gives more caliper clearance. That’s because the shape of the wheels was similar to the original. These are dually wheels, which have a design that gives lots of space for calipers, so no issues for me!

  • Jeffrey Torbert 2 years ago

    Do you have to do any modification the the width in the front the old trucks seem to have a narrower track width. I just purchased a 51 dump truck and am wanting to do something similar. Thanks Jeff

    • Nick Jeffrey Torbert 2 years ago

      Hi Jeffery,
      Actually yes, we had to do some things to make this work, and more importantly, look right. We opted to remove the dually front hubs, and swap them for the non-dually front hubs, to decrease the front track width by about 7″. Unfortunately, this wasn’t going to work, as the calipers would now hit the hit the dually wheels. So, we picked some 1″ spacers, which moved the wheels out enough to clear the calipers, but still kept the overall track width reduced 5″, which put the outer edges of the tires nicely inside the fenders, giving us the desired “looks like it belongs on this frame” look we were after. I’ll be posting an update to this article with pictures of the wheel fitment so check back soon!
      I hope this helps!

  • Jim 2 years ago

    Great work. Funny thing is when I first looked at the “original” truck (similar to one on http://www.classic-carstore.com) it looked like it was a “custom” truck in its time with the Windshield “Shade”. Great article on the frame work, good visual with photos. Thanks… Jim Lowrey https://www.Classic-CarStore.com

    • Nick Jim 2 years ago

      Thanks Jim!