340/4-Speed: 1970 Plymouth Duster Racer

In the 1960s, the Valiant was a solid car, but not necessarily exciting. Plymouth changed that in 1970 when they brought out the Duster, a semi-fastback coupe that was a Valiant in the front and a sporty new car in the rear. It sold well, including the muscular Duster 340, and would be in production through 1976. This 1970 Duster is a “half and half” – part Duster 340 painted in Violet (aka Plum Crazy in Dodge circles) and part Duster Slant Six in Lime Green. It’s going to need body and interior work but has a lot of newer parts, some performance. Lurking in Las Cruces, New Mexico, this Duster is available here on eBay where the no reserve auction is hanging at $4,600.

As the story goes, this Duster 340 was a drag car some 40-plus years ago. So, in order to go faster, the decision was made to lighten the car and this was done by transferring some of the existing sheet metal over to a Duster that started out with a Slant-Six engine. I can’t imagine just how much weight this saved, but the In Violet-painted fenders, hood, trunk lid, floorboards, rear-end, dash frame, steering column, and fender tag were all relocated to a body painted Lime Green. I guess you ended up with a Lime Violet Duster 340 (or is that a Plum Lime or Crazy Violet?).

The transformed car has not weathered well in subsequent years. Some of the merged sheet metal is crinkled here and there and the rear quarter panels are sporting some rust. We’re told the trunk floor has some small holes in it as well as another small hole in the driver’s rear footwell. Inside the car, new door panels are coming with the car to replace the ones that are/aren’t there, and the front seat is going to need recovering along with new carpeting. The dash pad looks surprisingly good although there is a hole in the dash where the radio once was (it’s coming along, too).

There is no mention if the 340 V8 is original to the car, but it’s said to run and drive. The car comes with a 4-speed, presumably moved over during the transition. It wears front disc brakes, too, which would have been standard with the Duster 340. The seller says thousands of dollars have already been spent on the installation of new parts, which include tires, clutch, radiator, engine harness, Hooker Headers, front brakes, and carburetor. The car has also just been winterized, although I’m not sure what’s required for the winter months in New Mexico.

Plymouth built just under 25,000 Duster 340s in 1970. They were popular then – and popular now. A really nice Duster 340 can easily be a $30,000 proposition these days. But how much would a hybrid like this be worth when the work is all completed? The fender tag and VIN would likely match and tell you it’s a Duster 340, but do the non-340 body parts make any real difference?


  1. Moparman Member

    It seems odd to me, and I don’t profess to be the expert here; (IMO) someone spent a lot of time changing unnecessary components for “weight savings”. IIRC, during the early years, the only difference between a /6 and V-8 is the V-8 K frame member. In the interests of mileage, a “Feather Duster” option came into being that sported aluminum components. This car, however, appears to be on the way to a good restoration candidate. GLWTA!! :-)

    Like 8
  2. DON

    And thats all the difference ! I think the green Duster may have been hit in the front and a junkyard supplied the front sheet metal and trunk lid ; the engine bay and interior floor look to have been resprayed with the intent on making the car purple. The VIN is for a 340 car too, and the green cars stripes look like the stripes used on a 70 340. This is a very early Duster too ; it has the 69 style Valiant cluster – most have the more familiar 70-76 wood grain type cluster, wit the exception of the early 340 Dusters having the 67-69 Barracuda cluster .

    Like 7
  3. James Appleby

    My second car was a ’74 Duster. I have absolutely ZERO nostalgia for these vehicles. It was absolutely the worst car I ever owned.

    Like 2
  4. Steve R

    The sellers story makes no sense. As mentioned above, the green car was like wrecked and the purple 340 car was stripped of its front clip and drivetrain to make one viable car. The “it was a race car” is often used to get gullible buyers to spend more than they otherwise would so they call tell they buddy’s at the local show an interesting story.

    This car should be valued as the way it currently sits, not some story that can’t be verified.

    Steve R

    Like 8
    • DON

      I sent the seller a message- He said the dash vin is the one for the purple car , so it looks like the dash may have been swapped out as well . I’m thinking the green one was a 340 car at one time too, and took a light hit . Maybe the title was lost, or it became a salvage title , so someone got the idea to swap vins with the purple one and paint the whole car purple to increase its value and to get rid of the salvage title.

      Like 4
  5. bone

    I’ve had a half dozen Dusters , and many other A body Mopars in the last 40 years. I’ve never had any issues with reliability or durability . The only issue they have, and here on the East coast ALL cars have is rust. They may not ride like a Caddy or handle like a Porsche , but they are a good size car and do the job that they were designed for

    Like 4
  6. Steve

    I’m going with Apple Green. I see more green than purple.

  7. arkie Member

    My brother had a Demon and a couple of my friends had Dusters. It seemed as if when you finally built the motor stout enough, the rear tires would not hook up coming off the line unless you were Ronnie Sox. As for this color, I’m calling it Eggplant.

  8. Ray Guardiano Member

    In my 45 years of Mopar-ing with the different body types & years, the A-body types all had their little problems but saw past them and made them better. I have had several Dusters (Dust-pan as my irreverent GM car buddies would call my car…lol) and I found them to be solid, reliable performers all the while allowing me to have the basis of my big engine, fast car antics of my youth on a budget. They accepted big block transplants fairly easily though necessary fenderwell headers were needed. So for some odd reason at age 65, I refuse to grow up and have in my stable TWO A-bodys, both with 505 Mopar big blocks, a ’65 Valiant Signet hardtop and a 1968 Valiant Signet 2 door post that I drive & enjoy on a regular basis. The A-body cars were and still, in my opinion, very good cars & that this old bird still enjoys reliving my youth with. Be well & stay safe… and Happy New Year EVERYBODY !!
    Old Gray Haired Mopar Ray

    Like 7
  9. JoeNYWF64

    Not a 1970 duster dash – no provision for a factory tach either after ’70 – dumb.
    I didn’t know the factory painted the floors body color inside! kewl.
    A step backwards with this new car in 1970(like with the maverick) with a hand pull emerg brake.

  10. martinsane

    The rear end, specifically the tail lights on 1970 are the best of all the years, exluding the Demon of course and yes i know Dodge vs Plymouth but still same darn car.

  11. erik johnston

    There is no weight saving with the swaping of the mentioned parts.As for the dash,70 71 dusters came with a rally dash that had had the usual gauges ,but you had the option for a tach. this dusters dash looks stock-not changed out. The racing history-nothing serious. This is still a great fixer.

    • JoeNYWF64

      Oops – i meant 1972 & later with only the big rectangular speedo available – no room for factory tach.

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