Dual Duty Truck: 1971 Chevrolet C20

Well here’s a little something you don’t see every day, a Chevrolet C20 Camper Special with a hydraulically activated dump bed. It’s certainly the first one that I have encountered. This dual duty truck is located in Bennett Colorado and is for sale here on eBay with a starting bid of $5,000. As of this writing, there are no bids.

This truck doesn’t appear to be modified in the bed-down mode but the description gives no indication of how or when the work was done other than to state that it works “perfectly”. With 85,000 miles on the clock, this truck would be considered lightly used taking into account that it is 48 years old. There are some bumps, bangs, and bruises but nothing beyond the realm for a work truck of this generation.

The hydraulic dump mechanism appears to be basic, simple and effective, it’s unfortunate that there is not more information on how it was developed. This arrangement does allow for great utility – think how many times the only way to discharge a load from a pick-up is via a shovel and your back – not to mention the damage done to the pick-up bed. This design would be great for annual mulch duty!

As for the body and exterior, there is evidence of worn-out paint and missing trim but all relatively minor issues. There are no images of the frame or floor pans but the owner states that the floors are good and a picture is coming.

Under the hood is a 300 HP big-block 402 CI engine in place of the usually found 350 CI motor. The story of the 402 CI motor, which was in production between 1970 and 1972, is a bit confusing. It is really the venerable 396 CI motor with an overbore of .030 “. As a matter of fact, all 1970 396 CI engines were in fact 402 CI but they were never referred to as such, they used either the 396 designation or were referenced as a “400 Turbo Jet” engine. The designation used depending on the model of the vehicle where the engine was to be domiciled. This became especially confusing as there was also a 400 CI “Turbo-Fire” engine based on the small block (327-350 CI series). Why Chevrolet just didn’t call it what it was, I’ll never know. Tightening emission control regulations spelled the end of the road for the 402 at the conclusion of the 1972 model year. The 402, along with its bigger brother the 454 CI engine, were notoriously “dirty” running engines. Chevrolet shouldered on with the 454 CI engine but in the greatly emasculated form to comply with the pollution regulations. Attached to this 402 CI big block engine is GM’s famed Turbo-Hydramatic 400 transmission and there are front disc brakes to bring this rig to a safe stop.

As for the interior, that’s a bit of a different matter. While it’s not bad overall, there is evidence of this truck’s life spent in the sunny west with a cooked dash pad, again, not a major issue to rectify.

So what do you think about this dual duty truck? Chevrolet and GMC pick-ups made between 1967 and 1972 are some of the hottest on the planet right now from a collectability perspective and this truck falls right into that category. It’s dual nature, however, would seem to lend itself better to work or commercial duty.


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  1. Chebby Staff

    New dash pad is readily available, in green, for about $80. Parts for these trucks are so cheap.

    Like 2
  2. Chebby Staff

    Dumper Special!

    Like 3
  3. Jim22

    This was literally a dream of mine every time I had to unload firewood from our 72 C-10. Man we beat the heck out of that truck. Three on the tree inline 6.

    Like 9
  4. Mark

    I’ve seen several pickup trucks modified like this. There are actually kits available for the mod, if I remember correctly the price is $3999 or so. Very handy for landscape contractors to haul mulch etc., also very good for small time contractors. New, they are probably little too expensive for most homeowners but I used to like this could easily fit into many homeowners budgets.

  5. Bob S

    I have seen a few truck boxes modified into a dumper, and I would love to have one. I have a Bobcat and an excavator, and there are many times that I could have used a truck like this for hauling small loads, such as topsoil and mulch.
    I would be interested on how he is driving the pump for the lift cylinders. I was thinking of modifying my truck, and I was going to use the magnetic clutch from an A/C unit to drive a pump.
    Back when these engines were available, the GM sales guy I knew told me that if you ordered a 400 2bbl, you got the small block. If you ordered the 400 4bbl, you got the big block.
    I had a truck with one, and they were just a slightly larger 396, and with the TH 400, it was a good combination.
    The cosmetic issues with the truck wouldn’t matter at all to me. I would put it to work tomorrow.

    Like 6
    • Mark

      The kits that I’ve seen had an electric pump to drive the hydraulic system. That’s probably the ease option, much simpler than something driven off the engine.

      Like 4
  6. Jwinters

    I used to be a dealer for Venco, they had pickup bed hoists, powered by an electric /hydraulic pump like a tommy gate has. the city of las vegas ordered 3 of them and the first time they dumped a load of dirt in the bed and tried to lift the bed they complained it wouldn’t lift it. we found the hoist just pushed right through the floor of the bed as the metal pickup beds are such thin metal they were never meant for that. so we had to reinforce under the bed with steel plates. light duty only!

    Like 2
    • Bob S

      I am familiar with the stresses on dump boxes, as I also own a C65 dump truck. I am thinking of downsizing to reduce licensing and operating costs.
      In actual fact, I am presently looking at an aluminum slide in dump box that I am thinking is a better solution for me. I am in the process deciding whether or not to commit to the purchase. This way, if I changed pickup trucks, I would be able to transfer the box to the new truck.
      The price of the slide in dump box is already considerably lower than the current bid price on this truck.

      Like 2
  7. Ben T Spanner

    My uncle was a home builder had a 1948 GMC pickup with lift on the pu bed. When he bought a new 1955 GMC, he kept the 1948, as it was handy.
    I live in SW Florida, and we had a lot of Hurricane damage to tile roofs. Many of the roofers now use dual axle dump trailers vs dump trucks. Many already have large pu’s to tow the trailer. Leaving the trailer in the driveway takes up less room. Initial cost, insurance and licensing have to be a lot less.

    Like 2
    • Bob S

      There are a couple of dump box trailers in operation locally, and that is also an attractive option. They are more costly than the slide in boxes, but are made to handle a heavier load, and can also be used to haul equipment.

  8. Redwagon

    At $5,000 this seems like a great deal assuming everything works as it should.

    Like 1
  9. SeanR

    My grandfather had one of these, same color and approximate year (I was about 9 at the time). I remember him showing my dad the conversion to dump bed and that he was thinking about selling the conversions. I haven’t seen one since!

  10. Chris Londish Member

    We had a similar conversion here in Australia Holden 1 tonner with aluminium tray with a electric hydraulic pump but that would be handy for unloading the camper

  11. Mike

    There’s a guy local to me with a dump conversion under his 3/4 ton square body. You can still buy the kit. One place I know of that sells them is Northern Tool. I thought about buying one for my ’78 K-35, but, decided to buy a used C-70 instead.

  12. Little_Cars

    Makes the ol’ pickup more practical in my opinion. Love it. Want it. Can think of hundreds of uses for the dump bed around my farm.

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