Endless Potential: 1947 GMC 3100

Think of all the things you could do with this GMC truck! You could fix it up enough to make it a driver, it could be fully restored back to pristine condition or it could be built into a cool looking rat rod. If you are into patina, this truck has it and it really looks great. Of course, what happens with this truck will be up to the next owner. If you would love to take this truck on, you can find it here on eBay in Sweet Grass, Montana with a current bid of $3,100 and no reserve!

The seller notes that the cab corners are in alright shape, but there is rust in the floors and door bottoms. As you can see, there’s a fair amount of work to be done on the inside, but it appears that all the major components present. Since it doesn’t run, there’s no way to know what kind of condition things like the gauges are in, but hopefully, they work or at least are restorable.

One of the only hold ups from fully restoring this truck is the lack of the original engine. Given that it’s long gone, it does help make a good case for a modern engine swap. Whether you decide to install a small block V8 or an LS, it sure would make for a fun build. So, what engine would you drop into that empty engine bay?

There’s a lot of work to be done here, but what a great starting point for a project. It’s potential is really only limited by its next owner’s imagination. If it were mine, I would fix any major rust issues, treat the body and frame with Waxoyl, and install a built Chevy inline six. That’s just my tastes, but I’d love to hear what you would do with this cool old GMC?


  1. Dave

    Rat Rod! Rat Rod!

  2. geomechs geomechs Member

    Restore! Restore! Find a rebuildable engine and go for it. This is an early Advanced Design and there aren’t a lot left. The sheet metal is too good to rat this one. I really wouldn’t complain (much) if someone stuck a newer six in it.

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    • Chevy Guy

      Agreed. Restore to factory spec. Please dont rat rod whoever buys this. They are so cool in original from, but just not as cool completely built with new stuff.

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      • PatrickM

        I completely agree!! I wish I had the money and place to work on and store this guy!! I would definitely enter the bidding. I have always loved these and their Chevy cousins. I actually prefer the five-windows. Buuut…this will definitely do the trick. Gloss black paint all around.

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    • Ken

      I’m not a fan of installing V8 engines with computer-controlled technology into old iron like this. When you do that, you’re stripping away what makes it special and turning it into just another boring restomod. I’d source an original 248 for this baby. Keep it Jimmy.

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      • David Ulrey

        I’d go against the grain somewhat. I’d get ahold of a 292 6 cylinder and build it up a little. Yes I know they aren’t great on gas but it would different and not stick out like a sore thumb and wouldn’t be another of many sbc trucks out there. I like LS engines but wouldn’t do it unless I planned to spend an incredible amount of money on the truck all over. My 2 cents worth.

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      • geomechs geomechs Member

        A 292 is a righteous engine. Well proven and built to pull. I worked on lots of them when I worked for GM. For this I’d look more toward a 302 but have to admit that a 292 would be a lot easier to find…

  3. Kenneth Carney

    …Maybe a newer 235 or even a 250. Wouldn’t turn down a 3800 V-6 if one came my way. I’d mate the engine to a 4-speed gearbox, add a newer radiator, a radio, sort the brakes, and drive it while I saved my coins to get it painted and reupholstered. Then, I’d put her where she belongs–back to work. Oops! She’d make a great EV too!

  4. 427Turbojet 427Turbojet Member

    Find a 50’s GMC 228 248 270 or even a 302. Old hot rodder’s engines, would give Ford flatheads fits. If you find one, the displacement is stamped on a little shelf on the block next to the distributor. Quite a bit of speed equipment around for them and they respond well to a little breathing on. Will bolt up to same era Chevy bellhousings and use several parts/accessories from Chevy 216s or 235s. I’ve dug up a few of them, have a 270 slated for a ’39 Chevy sedan delivery. If you read the California Bill’s guide to hopping up the GMC six, the engine mount adapter is a small rectangle of 1/4 steel with 4 holes (2 threaded) and move the radiator to the front of the mounts. Old school hot rodding at it’s best!

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    • geomechs geomechs Member

      Saw one of these with a 302. Souped just a little, with split manifolds and a 4bbl. Went good and had a unique sound…

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  5. geomechs geomechs Member

    Like I said, always look great with a full resto…

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    • PatrickM

      A picture IS worth a thousand words

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  6. Chris M.

    Stock appearance outside with later engineered underpinnings. Stop any major corrosion and leave it as it appears. A 5.3 LS and an OD auto would be a beautiful thing in this old girl.

  7. blyndgesser

    I’m thinking a baby Cummins R2.8 with a modern five-speed. More power and torque than the factory 228, but still low key and drivable.

    • Chevy Guy

      Nooooo! If your going to put a diesel in it that’s cool but please keep the original brand. Put the Duramax in the colorado in there!

  8. Ken

    Once again, you are using Chevrolet nomenclature to describe a GMC truck. This is not a Chevy 3100, it is a GMC 100. I have pointed this out several times, but no one at Barn Finds seems to get it.

    100 – 1/2 ton
    150 – 3/4 ton
    250 – 1 ton

    Like 1
    • Josh Mortensen Staff

      Sorry, we don’t always get the nomenclature right Ken. We will try to work on that.

      • geomechs geomechs Member

        Actually this one is a 9300, which is a Canadian truck. It would’ve essentially been a Chevy with GMC grill and badging. It would’ve run the old babbit-pounder 216. Old GMC Trucks website has a listing on Advance Design GMC trucks and their model designations…

        Like 1

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