Is This The Oddest Dually In America? 1985 GMC 3500 With An Inline Six And Manual Three Speed?!


Is This The Oddest Dually In America? 1985 GMC 3500 With An Inline Six And Manual Three Speed?!

My favorite “layout” for a dual rear wheel truck is exactly what you are looking at here. I like the “phantom” dually look with the eight foot fleetside bed and I love ’em with a standard cab. It is also likely the most useless layout for one of these trucks but we all like what we like and that’s how it goes. This truck punches all the right buttons for me. It sits right, has the cool late model wheels, I dig the white paint, it has no rust or other visible crappiness happening and then we get to the engine bay.

Obviously GM did not build fleetside dually trucks from the factory so this one is a person’s project. A person that left a 292 inline six and three speed manual transmission in the nose of this truck. I have plenty of personal experience with the 292 engine and love them like the draft horses that they are. Meant to work and work and work, they will do just that and likely until the end of time. They make little power, though and when you see a big square jaw dually like this one you are immediately thinking big block, right?

Obviously the swap would not take all that much work because the engines basically install themselves in these trucks but it must be weird hearing this thing going down the road with that screamy exhaust sound from the 292 coming from the dual tail pipes.

A 496, an M22, and a Gear Vendors would basically transform this thing into my dream truck. How would you “finish” it?

Craigslist Link: Is This The Oddest Dually In America? 1985 GMC 3500 – straight six?!


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13 thoughts on “Is This The Oddest Dually In America? 1985 GMC 3500 With An Inline Six And Manual Three Speed?!

  1. jase

    Great truck!

    I’d leave the 292 in there..Headwork, EFI and a turbo limited to 8 lbs, a 6 speed manual, and 4:10’s in the rear… Nothing else like it on the road…

  2. Kenny Badler

    My guess is that the seller originally intended to put an appropriate motor in it. But when deciding to sell, perhaps he thought \”If I put my $5,000 motor in this truck, will I get $5,000 more dollars for it?\” Even if the answer is yes, its still not worth it.

  3. Kenny Badler

    My guess is that the seller originally intended to put an appropriate motor in it. But when deciding to sell, perhaps he thought “If I put my $5,000 motor in this truck, will I get $5,000 more dollars for it?” Even if the answer is yes, its still not worth it.

  4. F.R.O.

    Give it a great detail job, and make under the hood spotless. Change out the rear bumper to a stainless/chrome one. Polish the bumpers, wheels, trim, and mirrors, then have them clear powder coated, so I\’ll never have to worry about them rusting or dulling. If the interior is clean as the outside, I\’d just add an auxiliary cord for the smart phone. Then I would upgrade the lighting to some brighter bulbs, or maybe LEDs or hids if the electrical system could handle it.

  5. RK

    As these American straight sixes disappear from the streets, the more I miss the sound.
    This ride needs only some of what the above commenters have stated (turbo, five or six speed, light cosmetic improvements) otherwise its pushing the right buttons for me.
    Anybody know what kind of wheels those are? Best looking truck rims I’ve seen in a long time.
    Until I can get me hands on one like this, I’ll just have to listen for UPS trucks and old Jeeps to hear that inline six music

    1. Don Bowman

      Alcoa made rims like that in the late 80’s- early 90’s. The caps on front look like stock dually of that era.

  6. C.M. Bendig

    That is a Miss match of parts. The rear end if from a Solid Beam axle stake bed. That would have only came with a TH400 or the low plus 3. The Saginaw 3 speed was a C-10/C-20 transmission in those years. 87 C-20 only.
    Stake bed trucks have a rear that just fits under a regular bed.

    I have the factory frame hangers for front leafs springs. I could make that a 7/8th ton 4wd or a front beam axle truck. I think ( have the factory rear hanger shackles but those you can use aftermarket or home made units. Just have to put a bushing in the frame if I recall right.

    I say 7/8th ton because Ill bet if you park that next to a C-30 and another C-20 it has the 3/4 ton frame. Yes Virginia they are different.

  7. Gary

    I am surprised to see the rear inner fenders look stock. Makes you wonder why the factory used those big fiberglass fender flares.

  8. sbg

    Such a hater. Straight 6s built America. What happened to you Brian? A 496? why not a screaming 2 stroke Detroit Diesel? Sigh

    1. Dan Barlow

      I’d like it better with regular 3/4 ton wheels on a full floater rear . Yeank that six ( I’m not a fan ) for a big block . My car has a 6 speed so in a truck I’m thinking a 400 with a overdrive put on the rear of it .

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