1970 AND ’71 —years that will live in infamy in the minds of Mopar mavens. Why? There were three seemingly-minor ”technical innovations”: First, in 1970 the “heavy rod” (Six-Pack) engine was introduced, by midyear, the cast-crank 383 2-Bbl, then, in M.Y. 1971, the 360 engine was introduced. So what, you ask? Answer: These were the first Chrysler engines that were externally balanced. In this arrangement, referred to as “Detroit balance” by various left-coast speed-parts merchants, some of the counterweighting required to balance the reciprocating/rotating assembly—the crankshaft, rods (w/bearings), pistons/pins, rings—are hung externally, up front on the vibration damper, which, in this case, can accurately be referred to as a balancer, and at the rear, on the flywheel, or torque converter or drive (flex) plate.
Then, in 1972, the cast-crank 400…
