There is a theory making the rounds that some plants only stamped "high performance" engines early in the '68 model year. If someone has an opportunity to inspect a couple of 440 c-bodies, more light may shine on the subject.

I have a "feeling" with no "HP" stamp and no apparent VIN stamping, this engine may simply be a good close date replacement.

Great looking car!! Both engine and trans are stamped in this 383 4bbl auto Hamtramck assembled Charger (324 SPD).