The Charger was offered in several trim levels, and, as with domestic Chargers, the high-performance version was designated R/T. The standard R/T engine was a 265-cube, two-barrel Hemi 6, rated at 218 hp. From there, the Charger R/T buyer had a choice of two much more exotic versions of the Hemi 6: the 248hp E-37 and the top-of-the-line E-38. Both of these engines featured a special induction system composed of three 45mm DCOE Weber side draft two-barrel carburetors, mounted on an individual runner intake directing the induction straight into the cylinder head's runners. It was a fantastic system that performed as well as it looked, offering both greatly improved torque production and more top-end horsepower. However, the success of the system didn't come without some effort. Getting the induction dialed in was accomplished by sending an engineering mule based on a Valiant Ute (utility) that had been fitted with the hot Charger's powerplant, directly to Weber's manufacturing facility in Italy.
The induction system-dubbed the Hemi/Weber Six Pack-was awe-inspiring. Along with an increased compression ratio at 10:1, more camshaft, factory full-tube headers, and a host of durability mods aimed at high-rpm longevity, the E-38 set a high-water mark in both output and performance, with 280 hp and 14-second quarter-mile times. That performance level put the Charger just shy of the radical Ford 351 Cleveland-powered Falcon GTHO Phase 3, but well ahead of the GM/Holden 350 Chevy-powered Monaro GTS coupe. As with the sporty Pacer models of the Valiant, the R/T Chargers were only available with manual transmissions and three-speeds. The straight-line acceleration is even more impressive when considering the combination of gearing and transmission only allowed for one shift over the course of the quarter-mile. The Charger E-38 came out strong on the production-class, road-racing scene, but at the high-speed '71 Bathurst event, Ford's GTHO Phase 3 Falcons cleaned house. The Charger's gearing with the three-speed manual transmission really compromised the car, making it impossible to gear for both lightning-quick acceleration and cover the top-end required on the high-speed straights.
In June 1972, the Charger finally got the four-speed manual transmission it needed: an Australian-built Borg Warner unit. The engine designations were changed at the same time, with the old E-37, the base Hemi/Weber Six Pack, getting the designation E-48. The top of the line Charger R/T engine-the new E-49-was even more radical than the E-38, the previous top dog, with a higher compression ratio, an even more radical camshaft, and a rated output of 302 hp. The E-49 was the pinnacle of achievement for Chrysler of Australia, and, at the time, the E-49 version of the 265 Hemi was recognized as the most powerful, regular-production, six-cylinder passenger car engine in the world. The E-49 covered the quarter in the low-14-second range in stock trim, a performance level that earned it the distinction of being the fastest production car ever built in Australia, a position it maintained for decades. Despite the improvements, the E-49 failed to take the win at the Bathurst event. that honor went to a ringer model of GM's Torana compact, the GTR XU-1 "72 Bathurst" special, released in late 1972 specifically to compete in the event. An updated GTHO Phase 3 Falcon took the second spot, while the Charger E-49 finished in third.