The Big Wedge - Mopar Big-Block Engine

Mopar's big-block "wedge" engine certainly never enjoyed the spotlight that surrounds its close cousin, the Hemi. The wedge may not have the glamour factor of those broad valve covers, but it delivered the kind of power that fueled the mystique of the performance car era. Introduced in 1958, the Chrysler wedge certainly had some big shoes to fill, as the famed 392 Hemi was in its last year as Chrysler's premier engine. That's Chrysler--a company that built its reputation on engineering, and high-output, bulletproof powerplants. In the large Chrysler 300, the new wedge didn't disappoint, but the then-new engine series really caught the limelight in 1962 when the Max Wedge came on the scene.

Built for unrepentant power, the Max needed no excuses and went on to sweep the floor for the next three years in sanctioned competition. The wedge worked, but in a twist of irony, the Hemi re-appeared in 1964, forever usurping the reputation as top-dog of the Chrysler camp. The 426 Hemi bore no resemblance to the earlier Hemi mill, but in fact was primarily a top-end modification of the basic Wedge big-block design.

The Chrysler wedge was built in two different basic configurations, each with a distinct deck height. The "low-deck" B-wedge featured a deck height specification of 9.98 inches, and carried a 3.375-inch stroke. OEM displacement variations began at 350 cid at the inception, and expanded to 361, 383, and 400 cid, determined by bore size. The 10.725-inch tall "raised-deck" RB wedge carried a longer 3.750-inch stroke and was available in 383, 413, 426, and 440-cube displacements, again by virtue of differences in bore diameter. While the Hemi basked in the fame of its racing success, the wedge went on to rule the streets, at least by virtue of sheer numbers. When the musclecar era was in full swing in the period from 1967-71, Chrysler was in the thick of it with legendary cars like the Charger, the GTX and Roadrunner, R/Ts and SuperBees, Challengers and 'Cudas, not to mention the big-block A-body Formula S and GTS. Here, in the midst of muscledom, the 383 and 440 wedge were everywhere, while the limited-production Hemi was a rare sight indeed. Would there even have been a "musclecar era" as we remember it without the ubiquitous Mopar wedge?

Mopar big-block wedge production ceased in 1978, and that could well have been the end of the story, but for the sheer devotion of Mopar musclecar enthusiasts. Interest in these old cars, and the engines that powered them, just never seems to diminish. As a result, parts development for the wedge engine has never slowed. To the contrary, really, there is more support, speed equipment, and ongoing R&D in the world of wedge power today than there ever was--far more. In what may play out to be another ironic twist in the evolution of the wedge, it can be argued that with the current state of parts development, the wedge design has more power potential than the Hemi that stole the limelight all those decades ago.

T&B Performance, of Monroe, Wis., thought so. The wedge featured here was built to compete in Popular Hot Rodding's annual engine building competition, the Engine Masters Challenge. It was the only Mopar at the event, and interestingly, the only Mopar happened to be a wedge, not a Hemi. Surprised? If previous experience is anything to go by, the wedge seems to carry an advantage. In fact, in the 2003 event, a Mopar wedge set the highest peak power level in the competition. [That engine, in fact, was built and fielded by the author, Steve Dulcich. -ed.] Super-high output wedge combinations wouldn't be conceivable without the continual refinement of aftermarket power parts, but there is a great deal of validity in the original design. In fact, the T&B wedge is deeply rooted in the original factory platform. Actually, its foundation is a factory 383 Mopar block cast in the year when the Plymouth's Road Runner first laid tire to the tarmac, in 1968.

Prepped with a 0.040-inch overbore, the factory block is stuffed with a 4.375-inch stroke crankshaft. The result is a 1.00-inch stroke increase that would have been unimaginable to the factory engineers all those decades ago. The stroker crank adds 123 cubes to the low-deck wedge, far eclipsing the cubic capacity of the largest of Mopar's factory wedge offerings. The block was fortified with a short fill of Hard Block, adding some additional rigidity to the bottom-end while helping to buttress the cylinder walls. The bottom-end arrangement is all stock Mopar, including the main caps, although reinforcement was added in the form of a main girdle from Chenoweth Racing. Brenda Foley of T&B commented, "The nice thing about the Chenoweth girdle is that there wasn't any external machine work involved in putting it on. It's just a matter of mic-ing it, and setting your heights properly. For someone who doesn't have the machines to mill off the tops of their maincaps, I think it would be a good add-on."

These long-armed crankshafts for the wedge are not an unusual novelty, but are readily available as off-the-shelf pieces from a variety of suppliers. This one is from Eagle Specialty Products, and is just one of several stroke lengths stocked by Eagle. Aftermarket cranks for Mopar wedge engines are commonly available in a choice of the factory 2.375-inch rod journal diameter, or with the 2.200-inch dimension of a factory big-block Chevrolet. The Chevy journal carries a three-fold advantage, reducing bearing speed and friction, while providing increased crankcase clearance, and allowing a much broader range of choice in aftermarket rods. The rods used in this engine are also readily available, a set of H-beam Eagle units in a 6.700-inch length.

The rods and crank received minimal prep; the crank counterweights were mildly profiled, and a Teflon-based oil-shedding coating was used on both the crank and rods. Brenda Foley explained the concept: "The oil-shedding coating is kind of like wax on a car. Instead of the oil really sticking to the crankshaft, it just allows it to shed more easily; we were trying to keep the windage down as much as possible since we did not have the wide kick-out pans the Chevys do." Further helping to reduce windage is the re-directed drainback achieved through modification in the lifter valley, Brenda continued, "We were trying to keep as much oil off the crankshaft as possible, to keep the windage at the minimum. It doesn't have much room to go when it is stuffed between the crank and the block."