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Factory Sunroof: 1973 Plymouth Duster 340

For 1970, Plymouth introduced the Duster fastback, a sporty version of their Valiant compact. It was an immediate success and would spawn Dodge’s derivative of the car, the Demon (later called Dart Sport). If you wanted to save gas, you got the car with a Slant Six engine; but if you wanted some muscle in the mix, you got the Duster 340 with its small-block powerhouse. This 1973 Duster 340 looks to have been ridden hard back in the day, but it comes with the seldom see sunroof option. St. Louis, Missouri is its current hang out and the car is available here on eBay via a no reserve auction standing at $3,550. This car will find a new home soon.

The 340 V-8 is one of the best remembered motors from the 1970s muscle car era. They were lightweight and quite potent at 275 horsepower. Many Chrysler products sported them at the time, including the Barracuda, Challenger, Charger, Dart, Road Runner – and Duster. From 1967 through 1973, the “Little Giant Killer” (nicknamed that because it could compete with much larger powerplants) found its way into nearly 217,000 Mopar machines. 1973 was the swan song for the engine, and upwards of 16,000 copies were installed in the Duster 340 for ’73 (its second-best Duster production year). Source: Swinger340Specials.

We’re told this ‘73 Duster 340 has been off the road for quite a while, spending its time in a private collection. While we understand that the front and rear frame rails are solid, a lot of the sheet metal is not. The rear quarter panels will need patching or replacing, and the hood, door, fenders, and trunk lid all show signs of cancer. There are also some holes in the floor pans and the photos supplied of the undercarriage indicate that a thorough inspection is needed before pulling the trigger. The glass has survived well, although the windshield has met a rock along the way.

The interior will need a fair amount of attention as well, from the seats, floor coverings and dash pad. Also, the console looks to have given up the ghost. The only signs of recent inhabitation inside this car is the old cell phone laying behind the shifter. The headliner is a mess, some of which may or may not have been caused by a leak from the ill-fitting factory sunroof, which was not a common option back in the day. As convertibles were on the way out in the mid-1970s, sunroofs had not yet taken their place on a volume basis.

We’re told this is a numbers-matching car with a TorqueFlite automatic, but that either the engine or transmission are stuck. This Duster has an 8 ¾ rear-end, but the gear ratio is unknown. The fender tag is intact so prospective buyers can further scrutinize their possible next purchase. The original owner opted for a few accessories to make life easier, such as power steering and brakes. Before you get your heart set on those old school mag wheels, they do not go with the car. Instead, it will be fitted with standard wheels and tires that will at least hold air for the trailer ride to its next home.

Classic car value guides suggest a really nice Duster 340 will set you back at least $15,000 and we’ve seen cherry examples go much higher. You’re not likely to end up with a financial windfall later by restoring this Duster 340 now, but you’d have a very capable street machine when you got done. Repainted in Lemon Twist, this car would stand out wherever you took it.


  1. piston poney

    i bet this is the same guy that is selling the 1970 Charger R/T the “private collection” state meant gave it away

    Like 8
    • flmikey

      You are absolutely correct, Poney…unfortunately for both of these cars, it may be too late to save them…

      Like 5
      • piston poney

        of the 2 the duster has better chances by alot

        Like 6
  2. Arby

    They got the “Duster” part down.

    Like 2
  3. DON

    In 1973 there was no 8 3/4 rear available just an 8 1/4 ; hopefully whoever put this one in modified the axles so the larger bolt pattern is the same for all four wheels. . Duster 340s all had power disc brakes as standard equipment . The air cleaner is wrong and the radiator looks to be out of a 318 car . Judging by the weird stuff growing on the console ,this ones been sitting a while,likely with the door glass at least partially opened. Usually the fenders and doors dont rust out on these , unfortunately, the rear 1/4s always do . The underside of the car looks surprisingly good , If the motor checks out to be a 340 and its not damaged , this could be a good deal. A lot of parts are now being reproduced for these, and there’s always a chance you can find a junk Valiant around for parts

    Like 8
    • stillrunners

      My A-body 4 1/2 bolt pattern 8 3/4 rear ends came out of 73/74 cars.

      Like 0
    • Nick

      Sure there were. Every A, B, and E body with at least a 340 (after 1971) had one, and nothing else. Earlier than 1972 had the same, unless you could (or had to) option in a Dana.
      You can clearly see it in the rusty under body pictures. 8-1/4 had a bolt on rear cover and was used on 318’s or less. A bodies of any vintage always had the smaller bolt pattern. The only difference (in the rear) would be the axles.

      Like 1
      • DON

        No, the 8 3/4 rear was not available after 1972 in A bodies . The V8 disc brake cars from 1973 and up had a larger bolt pattern then the early models.

        Other changes were in store for the Plymouth Duster. Simpler single-piston slider-type disc brake calipers were introduced for 1973 (standard on 318-powered cars and with power-assist on 340 models), replacing the Kelsey Hayes four-piston calipers. Disc brake-equipped Dusters now had the more-common 5-lugs on 4.5″ wheel bolt pattern. All 340 and some 318 engine-equipped cars received the simplified 8.25″ rear axle assembly (with wheel bearings riding directly on the axle shaft and endplay being taken by C-clips); these axles also featured the 5-on-4.5″ wheel bolt pattern. (This axle assembly replaced the 8.75″ “drop-out” arrangement seen on some 1966-1972 A-bodies). The 225-powered cars retained the 5-lugs on 4″ pattern on vehicles with the standard drum brakes.

        Like 1
      • MoPar Mike

        Nick. After 72 8 1/4 was the rear end used in A bodies behind 340s and later 360s. 73 and newer disc brake A bodies have 4.5″ bolt pattern not 4″. And I’m almost positive 8 3/4 was no longer available in B bodies from 73 on.

        Like 1
      • Nick

        Good to know Don. Though, the pictures still show an 8-3/4 axle under there, with what should to be the large bolt pattern.
        I’m thinking, against the odds maybe, that it was built with that rather than having it swapped in.
        If there was a rear end swap maybe it was from a 1970 model, with left hand threads still on the 1 wheel . . .

        Like 0
    • karl

      I took a 71 8 3/4 rear and put it in my 74 360 Duster ; I did have to have big bolt axles cut and resplined to match the front wheels ; I’m sure thats what happened with this car.
      – it was pretty common at the time unless you wanted to keep two spare tires in your car !

      Like 0
  4. Little_Cars

    Wow, two “Citron” Dusters in less than a week. Now we know how these lemons begin to rot. At least this one is more complete and with better features than the cheapo reupholstered bench seat Duster with no sunroof.

    Like 0
    • DON

      Well yes more complete, but the Dodge Demon is an earlier model which makes it more valuable , and its harder to find than a Duster 340 .as the Demon was only made in 71 and 72. The 73 340 cars dont command the money the earlier ones do , but this one does have some nice options , and the “Lemon Twist” yellow was the only color available at extra cost, according to my sales brochure !

      Like 2
  5. Shannon

    I think my buddy O’bannion might have owned this in the 70’s…..

    Like 0
  6. jokacz

    Oh Boy, it has shackles! LMAO

    Like 4
  7. Steve Bush Member

    You are correct piston pony. It’s the same dbag seller, 70f8beepost4404. And yes, he pulled the tire switch b.s. on the Charger too.

    Like 4
    • Al_Bundy Al_Bundy Member

      Gotta save some wheels for the next sales attempt eh ? List the car as it will be sold. Just the type of seller you don’t want to negotiate with…

      Like 8

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