Big 10 For You: 1980 Chevrolet Big 10 Pickup

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Everyone likes clean air.  The problem in the seventies was that the rather rapid implementation of clean air standards forced manufacturers to come up with complicated fixes to meet the letter of the law.  One of those fixes was the catalytic converter.  Designed to convert toxic exhaust gases into less harmful stuff by some sneaky scientific process, catalytic converters sadly robbed horsepower and fuel economy in the process.  Chevrolet ingeniously found a way around some of the more restrictions by offering a half ton pickup with 3/4 ton parts to lessen the emissions impact on some of their trucks.  This Big 10, being auctioned on eBay out of Gilbert, Arizona, is one of those unique work arounds.  This heavy duty C-10 must have caught the eyes of the Square Body Mafia, with bidding already hitting $9,300.  Is this rare truck worth the lofty price?

The story, which is told well on this forum page from, is almost one of serendipity.  The emissions regulations for 3/4 ton trucks in 1975 was considerably less onerous than those of 1/2 ton trucks.  Ford and Chevrolet both already built what was commonly called a “heavy 1/2 ton” truck if you selected the right options by accident or clever design.  Once Ford and Chevrolet recognized the advantages these option packages allowed emissions wise, the marketing guys got involved.  For Chevrolet, that package became the Big 10.  The Feds finally caught on to the ruse by the end of the decade, and the 1980 model Big 10 was saddled with the same emissions equipment as lesser models.  The model finished out the year and faded away.

The Big 10 was still a good deal if you wanted a full sized pickup with a little more capacity and capability.  Enhancements were made to the brakes, springs, and tires to bring the weight rating up.  These trucks were also equipped with a 12 bolt rear end and five lug wheels to round out the package.  Nowadays, extras in these areas are usually part of a trailer towing package.   The truck we see here also brings a 350 cubic inch engine, a TH400 automatic transmission, and air conditioning to the table.  It is also outfitted with the Silverado package.  Quite the truck.

While many square body Chevys suffer from rust through in a number of areas, this one seems to display only surface rust in a few areas.  The bed is not perfect.  However, there are precious few dents evident.  There are some signs that previous owners used the tailgate to leverage some heavy items into bed.  Looking at the rest of the truck reveals scratches, paint fading, and some areas that are devoid of paint.  The rust was likely held at bay by the dry Southern California and Arizona climate that the truck seems to have spent its life in.  If it were a Florida truck, I doubt it would still be cruising around in one piece.

The sun baking also took its toll on the interior.  To freshen up the truck, the seller replaced the dash, carpet, headliner, and the seat’s foam and cover.  While no mention is made of the door panels, I believe they have been reconditioned as well.  The plastic GM used to make these pieces was notorious for drying out and becoming almost granular in texture and bleached out in look.  As mentioned earlier in the article, the truck comes with an air conditioning system that has been repaired and blows cold.  GM had the best air conditioning in the business at this time, and parts are readily available for any repairs the next owner might need.

Things still look quite stock under the hood.  This comes at somewhat of a surprise, since the engine and transmission were rebuilt 20,000 miles ago.  Nobody who rebuilds a small block Chevy, especially one from the late seventies and early eighties, passes up making cheap and easy modifications to extract more horsepower.  Yet, here we have an almost showroom ready engine compartment.  Perhaps the engine was rebuilt in California.  I have heard that all emissions equipment must be retained for a vehicle to be licensed in that state.  Perhaps a reader may be able to clarify this for us.  Regardless, the ad states that the truck has covered just 74,000 miles.  I find that odd, and would probably guess the true mileage might be better represented with a one added to the front.

The only thing I don’t like about the truck is the price.  $9,300 can buy you a Square Body in a lot better condition if you look.  However, Big 10 versions are special, and they do represent an important transitional period for the American auto industry.  Implementing clean air standards was essential and inevitable,  It was just hard to give up horsepower to do so.

Auctions Ending Soon


  1. ChebbyMember

    I love that Agave Green color. I don’t think Chevy ever painted the wheels though….

    Like 4
  2. HoA Howard AMember

    Keep ’em coming, guys, that Z car is on the horizon. OMG, there’s wear,,,on the box floor, GASP, maybe it was actually used to haul something. I’m glad mine doesn’t have AC, adds a lot stuff under the hood. I could change a water pump( which I have to do) in half an hour, this would take days. Clearly, this is much better than mine, but if they’re getting $10g’s for nice ones, mine has to be worth $3 or $4. Maybe more, but I just can’t gouge someone like that. I got a deal, the next person should too. Quite frankly, after owning one now, I really don’t see the attraction. Certainly I’d never pay $10g’s for one in any condition.

    Like 6
    • geomechs geomechsMember

      Actually, Howard, they’re not that bad to change a water pump, with the A/C. That bracket just flips up, giving you complete access to the pump. The old square bodies were very nice to work on, and reliable to own and drive. I still maintain that the square bodies were the best that the General cam out with, as far as checking all the right boxes was concerned. A lot of these out west with 300K miles and counting…

      Like 5
  3. Classic Steel

    Has anyone noticed the banner that flashes on the screen lately? It’s an interesting counter on viewing of Barn Finds that locks out those who reached their limit. It seems like a great business model for those listing on this site. I think it’s great for a selling point for those placing advertisements to state a limited population excluding those other buyers that goes against the other bigger entities like Craig’s-List or EBay using the search words of project car or “Barn Find” which is interesting linked in most of the Barn Find web site. No worries folks as Classic Steel is just going to step out to other nonexclusive counting sites BAT or the other non-pay for view places like EBay. One might have thought maybe a counter to comments but the whole site with limited viewership that pops on the screen to say sorry your have exceeded viewership is king. :-)

    Like 13
    • HoA Howard AMember

      As a member, I don’t get that, however, there was a shameless plug for members a while back, calling non-members “cheapskates”. I know I promoted being a member, but I wouldn’t call non-members cheapskates. However, I will say again, I enjoy your comments, Classic Steel, why not just become a member? Still a fun site.

      Like 8
  4. stillrunners

    Nice truck and my 1976 Ford F150 was called a 5/8 ton….but funny it had 3/4 front and rear…..still haven’t worn er’ out……here moving my shop stuff in a gutted fifth wheel….

    Like 5
  5. ALEX

    Not a 1980 Silverado…wrong grille and no square headlites …would want some more history and check serial # and build sheet.

    Like 1
  6. GMoparman

    Either not an ’80, or has the wrong grille and fascia. 1980 Silverado trim has rectangular headlamps. Flipper perhaps?

    Like 1
    • HoA Howard AMember

      I read in 1980, you could get either round or square headlights, square was generally for the fancier trim.

      Like 4
      • geomechs geomechsMember

        1980 was a real transition year. The very first ones, I’m sure were carryovers from ’79, but as the year progressed I began to see different things. The oversized air cleaner was a 1980 item but the axial six A-C compressor was phased out for the R-4 by the end of December. The gauges changed from red needles to orange and there were definitely some changes to the seat upholstery; the seat upholstery here tells me that this is a very early ’80 or a ’79. The grill tells me that it’s a ’79. One final thing: In 1980 GM came out with a fuel tank switcher relay that would hold the tank switcher valve on the LH tank (if that was what you were running). Until then, the system defaulted to the RH tank; if you ran the LH tank the switch was energized then reverted back to the RH tank when the ignition was turned off. Trouble was, if your right tank was already full, you had a little bit of return fuel reroute to the RH tank at shutdown. That caused the odd gasoline drip and the environmentalists had a major coronary over those ‘harmful’ evaporative emissions. I don’t recall any ’80 models, even the ones built in the fall of ’79 NOT having that relay. Now, a big question I have here: TH 400 transmission? behind a 350? I’ve only seen TH 350 transmissions behind an SBC on a 1/2 ton, even a heavy 1/2 ton. Big blocks ran through a TH 400. 1980 was the year they introduced the lock-up torque converter on the 1/2 tons. It was somewhat troublesome and the way we usually ended up fixing it was to disconnect the wire to the lockup relay, and allowing it to be a normal transmission. Otherwise you had what was termed: a ‘chuggle.’ That was when the torque converter would continuously lock and unlock while cruising down the highway. I might add that it often forgot to unlock at a stop light and you would stall out…

        Like 4
    • local_sheriff

      Correct; if it were an 80 Silverado it would have rectangular lights and different grill with more and square holes.80 non-Silverados also used the new grill.
      This face is correct for a 77-79 truck, with bezels surrounding park lamps and with rectangular holes in the grill .
      If this is an 80, some PO must have replaced the square lamp setup and grill with stuff from an elder vehicle. IMO it’d make sense as I’m a bigger fan of the round lights, older grill look…this ain’t complicated as you’d only need replacing markers, lamps , bezels and headlight buckets

      Like 0
  7. v

    ah one of the rare green trucks . these green interiors are not available in restoration supplies. i have a green 79 k20 and i cant find green interior parts other than used.

    Like 2
  8. canadainmarkseh

    These were good reliable trucks, what killed the power more than anything was lowered compression ratios so that lead could be removed from the gasoline. The other pre combustion power killers were EGR valves which fed exhaust gasses back into the cylinders through the intake manifold essential making the engine eat its own $h!t. This along with smaller jets in the carb and ignition timing being back off had way more effect on power then the cats. Air pumps contrary to popular belief did not rob power, all they did was pump fresh air into the exhaust through a one way valve to produce a false reading of emmisons at the tail pipe. The non mechical regulators were fooled but air pumps but didn’t care as long as the readings were good. Today we us turbo chargers to get the power back in owwer lame low compression engines and tell the buying public what great things they are. All there doing is raising compression ratios back to pre emission times. Fuel milage in pickup trucks has not improved a lot. But what comes out the pipe has. The fact is it takes the same amount of energy to move the same weight mass whether it was built in the 70’s or built now. What has made the differance is lighter vehicles and improved aerodynamics. That why everything looks so cookie cutter these days it’s all about wind tunnel design, which narrows the the designers options. JMHO.

    Like 1
  9. mikeMember

    Looks like a bidding war… only two bidders, one against the other. $9,300 with two days to go. I wonder how many ebay car buyers there are who woke up the next morning and thought “crap, not only did I just buy a vehicle but I paid way too much for it”!

    It’s like the old saying that something, whether it is rare/old/gold coins, vehicles, houses, motorcycles, etc. is only worth what a person is willing to pay for it.

    One good thing about ebay vehicles is that if a buyer uses the “buy it now” option, they usually have to put up $500 right then and there, so if the “buyer” backs out, at least the seller gets something and the would-be buyer learns a somewhat expensive lesson about fantasizing about vehicles on ebay.

    Like 0

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