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Plymouth's pitch for the 1968 Road Runner was blunt: strip out the luxury, keep the muscle, and undercut everything else on the showroom floor. The cheap way to do that was a 383, a bench seat, and a rubber mat. The expensive way — and by far the rarest — was to tick the box for the 426 Hemi. This Sunfire Yellow coupe, currently up for auction on Bring a Trailer, took the expensive route, and it has spent 48 of its 58 years inside the same family.
One of 391
Plymouth assembled 840 Hemi Road Runner post coupes for the 1968 model year. Of those, 391 left the line with the three-speed TorqueFlite automatic rather than the four-speed manual, and this is one of them. The fender tag backs it up: RM21 for the two-door coupe, engine code 73 for the 425-horsepower dual-quad Hemi, transmission code 5 for the automatic, PNT SS1 for Sunfire Yellow, and a March 7 build date.
The rest of the tag reads like a checklist of what a Road Runner buyer actually cared about in 1968 — A1 for the 26-inch radiator, D9 for front discs, AX 68 for a 3.54:1 or 3.55:1 Sure Grip rear end, and Z8 for the blacked-out Performance hood treatment. The R1 code covers a two-watt AM radio, which tells you everything about where the money went.
A Drag Car That Came Back to the Street
Someone campaigned this Plymouth at the strip in the 1960s or 1970s. The seller's father-in-law bought it in 1978 and pulled it back toward street duty, a process that included fitting a replacement 426 Hemi and, around 1980, stripping the multi-color body-side artwork the car had been wearing and shooting it in the yellow lacquer it carries today.
That replacement engine is the asterisk on this car, and the listing is upfront about it. The block stamping decodes to Marysville, Michigan, 426 cubic inches, and a March 12, 1968 build date — period-correct hardware, assembled within days of the car itself, but not the numbers-matching block. Anyone who has watched a Road Runner cross an auction block knows how much weight that single detail carries.
What's Actually There
The five-digit odometer reads 11,000 miles, fewer than 2,000 of which were added under the current owner. The Indiana title carries an Odometer Exempt brand, so treat that number as a reading rather than a history. Chromed 14-inch steel wheels wear F70-14 Firestone Wide Oval red-lines, and braking comes from front discs and rear drums — though the factory power assist has been converted to an unassisted setup.
Inside, front and rear bench seats are trimmed in two-tone tan vinyl that carries onto the door panels, set against a black dash, headliner, and carpet. A Chrysler Solid State AM radio, a heater, front belts, and sun visors round out the equipment, and a three-spoke wheel with a horn ring fronts a 120-mph speedometer. The seller notes cracked paint in places and a chip in the right-front wheel well. The car is offered on behalf of the father-in-law with old photos, memorabilia, and that Indiana title in his name.
Reading the Market With Hagerty's Tools
Sticker context is worth remembering here. Per the Hagerty Valuation Tool entry for the 1968 Road Runner, the base car with the 335-horsepower 383 listed at $2,870, the 440 added $281, and the Street Hemi cost another $714.30 — roughly a quarter again on top of the whole car. That premium is precisely why so few buyers took it, and precisely why the survivors sit where they do today.
The modern picture is less linear than Mopar folklore suggests. Hagerty's own market coverage has flagged that 1968–70 Road Runners haven't yet found their footing with younger buyers, which has kept 383 and 440 cars far more accessible than their reputation implies — Hagerty has even folded B-body Mopars into its under-$60,000 muscle conversation. Hemi cars are the exception that proves it, and running the specific configuration through Hagerty's condition grades (#1 Concours through #4 Fair) is the only sensible way to price one, because the spread between a #2 and a #3 Hemi B-body is wider than the entire value of most 383 cars.
Where documentation is intact, the ceiling is very high — a museum-grade example of the Road Runner's upmarket sibling brought $374,000 as a 1971 GTX Hemi. Where it isn't, the discount is severe. Current asking prices for 1968 Hemi Road Runners on the open market cluster in the $95,000 to $130,000 range, and those are cars leaning on original drivetrains. A replacement-engine car does not compete in that conversation; it competes with well-sorted big-block cars, and it should be valued accordingly.
Where the Bidding Stands
As of this writing, the high bid sits at $29,250 with the auction scheduled to end August 22. The car is located in Evansville, Indiana. Whether the number climbs toward big-block money or stalls out will come down to how the room weighs a genuine 1-of-391 J-code shell against a Hemi that arrived 10 years after the car did.
For context on what the other end of the spectrum looks like, compare it against a fully restored 1968 Hemi Road Runner or a triple-black 1969 Hemi four-speed — and for the mechanical side of the story, a look at what goes into a rebuilt 1968-vintage 426 Hemi explains why a correct replacement block is worth having, even when it isn't the original.
