Power Point
Harold Didluck's 1968
Hemi Dart Factory
Super Stocker
By Al Kirschenbaum
During the late 1960s, Detroit's automakers were at war. What had started late the decade before as minor racetrack skirmishes between the Big Three car factories' hottest production musclecar models had escalated into all-out marketing combat. Year after year during that period, the new car makers introduced increasingly hotter combinations of high-output engines installed in smaller and/or sportier body styles.
Then, in the Spring of 1968, Chrysler Corporation dropped the big one. Or at least it was their automotive equivalent of nuclear fusion on wheels. After a long and glorious history of building production based maximum-performance NASCAR super speedway and Super Stock-style quarter-mile race cars, Chrysler rolled out a limited run of 426
Hemi-powered Dodge Darts and Plymouth Barracudas - their biggest engine in their smallest car yet!
Before we take a close look at our Super Stock feature machine here. Harold Didluck's Hemi-powered '68 Dart race car, a little more background information on factory Super Stockers would probably be in order. Back in 1967, Chrysler's Dart and Barracuda lines represented their lightest and sportiest production car models and the 426-cubic-inch Hemi V8 engine was their most potent powerplant. Combining the two
elements was a proven approach to maximum performance for Super Stock/B and Super Stock B/Automatic competition.
Unfortunately, these car and engine combos could not be properly mated on an existing Chrysler assembly line. Too many deviations from standard construction practices were required for everything to go together in anything approaching massproduction fashion. So rather than custom crafting each individual machine, Chrysler's "race group" boss Dick Maxwell contracted Hurst Performance Research to produce the Darts and Barracudas on their scaled-down and much more flexible "mini" assembly line.
In production, Chrysler delivered brand new Dart GTs bodies from their Hamtramck plant to Hurst Performance in Madison Heights, Michigan. Each car was shipped minus its powertrain, radiator, exhaust system, hood, window regulators and other equipment. After installing a special new front crossmember and reworking the right-side shock tower for clearance, Hurst installed the Chrysler supplied Hemi engine assembly, transmission, driveshaft, front and rear suspension systems, the rearend and the brake system. Hurst also fitted each Dart with lightweight side-window glass, acid-dipped doors, fiberglass front, fenders and a scooped 'glass lift-off hood.
During construction, each Hemi A-body also got an appropriate Hurst shifter, lightweight front seats from an A100 Dodge van, and Hooker headers and mufflers with a steel tube exhaust system that ended below the rear axle. Each car's battery was also relocated to the far right corner of the trunk and the rear wheel housings were reworked to make more room for big tires. All Dart quarter-panels were also flared for additional clearance and the entire car was finished only in flat grey primer.
Whether looking at either these cars' specifications or at the cars themselves, there is little doubt as to what they're all about. These were drag cars through-and-through. And at the heart of the combination was Chrysler's 426 cubic inch Hemi engine, the most potent V8 motor ever built for a domestic automobile. Originally pushed into production for eligibility in the 1964 Daytona 500, the 426 Hemi engine shared the same bore, stroke and horsepower numbers as the 1963-64 426 Max Wedge engine on which it was based (and, by'65, totally replaced). Fully assembled, the broad-shouldered 426 Hemi out weighed its predecessor by quite a few pounds, but it also made more than one hundred horsepower more than a comparable wedge-head engine.
In its most potent form in 1964 and 1965, Chrysler's now-legendary eight-barrel race Hemi engine (with a 12.5:1 compression ratio) was rated at 425 horsepower. Detuned for 1966 (and offered through 1971), the 426 Street hemi eight-barrel engine with a 10.25:1 compression ratio was also rated at 425-horsepower. And although the '68 Super Stock Dart's Hemi engine was a mechanical cross between the two earlier incarnations, it too was rated at 425-horses.
However conservatively Chrysler rated the Hemi, the key to the engine's uniquely high-specific-output was its deep-breathing ability. The fully machined hemispherical combustion chambers in the 426's cast-iron cylinder heads allowed larger unshrouded valves (2.25-inch intakes and 1.94-inch exhausts) than other chamber designs. In addition, the
valves' laterally inclined angles and the centrally located sparkplugs permitted generous port proportions for maximum airflow and efficient flame travel. Chrysler pioneered this high-output cylinder head design when its first 331-cube Hemi V8 debuted for 1951.
To complement the Hemi's capacity for air-moving chores, the '68 SS engine's eight-barrel crossram induction system was designed to provide sonic and inertia ram-tuning at high engine speeds. Based on the earlier 426 Max Wedge's intake manifold and specifically intended to feed large valves and cylinder head passages, the Hemi's aluminum intake casting utilized the sonic pressure pulses which formed inside the uniquely contoured inlet tract to deliver improved airflow and outstanding cylinder filling abilities. This, in turn, resulted in more power potential than conventional multiple carb systems offered. Like the late-1964 and '65 Race Hemis, the '68 SS motors also came with a pair of high flow Holley carburetors.
Other features of Chrysler's '68 race Hemi engine included a cross-bolted-main bearing block with generously proportioned casting sections and oiling passages, a chemically hardened forged steel crankshaft, forged steel connecting rods and forged aluminum dykes-ring pistons.
Driven by a double-roller timing chain, a production Street Hemi camshaft (referred to as "Stage II" in '68), used solid lifters and large diameter pushrods to activate cast-iron rocker arms riding on separate shafts for the intakes and the exhausts. A dual point distributor signaled a Prestolite Transistor ignition system when to send juice to each cylinder's centrally located spark plug. Like all production Hemi engines, the S/S Dart powerplants were carefully assembled by skilled technicians at Chrysler's Marine and Industrial Division in Marysville, Michigan.
To support its potent powerplant, all of the factory's Hemi Dart driveline and suspension equipment was upgraded to suit. In addition to special chassis and frame reinforcements, the multi-leaf rear springs were specially designed to provide proper chassis action for maximum traction. The remainder of the suspension system included six-cylinder front torsion bars and competition-rated shock absorbers.
The '68 Hemicar’s were also available with only one option; the buyers' choice of either an automatic or a manual transmission. Four-speed cars came with "slickshifted"internals, a 10.5-inch extra-duty clutch and flywheel inside a special steel bellhousingand, of course, a Hurst Competition-Plus shifter. Also Hurst-shifted, three-speed
TorqueFlite auto trans Hemicars were fitted with a high-stall B&M torque converter, manual-shift valve body and heavy-duty internal hardware and soft-ware.
While all manual trans Hemicars were fitted at Hurst with a super-duty Dana 60 rearend and a Sure-Grip differential with 4.88:1 gearing, TorqueFlite-equipped cars were assembled with an 8 3/4-inch limited slip rearend and a 4.86:1 final drive ratio. At the Hurst facility, the A-cars' front disc brakes were also replaced with big-car calipers and rotors with a full-size (4.50inch) wheel lug pattern.
Currently campaigned by Harold Didluck of Wainwright, Alberta, Canada, the '68 Dodge Hemi Dart Super Stocker shown here is one of the 50 original factory Darts produced in early 1968. To document that his "High Roller" is, in fact, a genuine Hemicar, Didluck's Dart still sports its original VIN (vehicle identification number) tag with the legendary "L023M8B" code stamped in front of its sequential number series.
For reference, the second character in the VIN code, the letter "O:' translates in all Chrysler literature as the factory's unique designation for "Super Stock." The fifth character, the letter "M," indicates that the car was built with nothing less than a "Special Order 8" - in this case the obviously very special crossram 426.
Racing this rare Hemi-powered fullbodied Super Stocker for the past eight years has been an exercise in dedication for Harold and his crewchief, Mike Stafford. Not only has this team of underfunded independents handled all of the problems normally associated with running a relatively heavy high-horsepower fat-tired drag car, most
of their powertrain and body hardware would now draw big crowds at a musclecar museum. Then when you consider that these guys live 225 miles from the closest dragstrip (Saskatoon, Saskatchewan), and the fact that there are probably less than a half-dozenHemicars in all of often-frozen Western Canada, you can begin to understand something
about what it's taken for them to run as hard as they have.
As far as Didluck is concerned, however, he credits most of his Dart's 9-second quarter-mile ability to a hardworking group of friends and helpers which includes Danny Smith, Dick Panter, Terry Pinoski, Kelly Andersen, Al McGechen and the Lee Brothers Performance and Machine shop in Red Deer, Alberta. At a grass roots level, these guys may be simply into going fast with Hemi-powered Super Stock drag cars. But geographically, mechanically and emotionally, this entire north country crew qualifies as true, "High Rollers." ·