cars under a certain size couldn't have more than 400cu

That became irrelevant when the GTO, 442, GS, and Chevelle had 455 and 454 engines.  The 396 became a 402 simply for decreased emissions.........

the 396 was such a popular and reputable selling point with people

I'll buy that reason, the 396 had a certain mystic..........

That Chevy dealer in Virginia Beach, where I bought the Camaro had a ship-load of Yenko Deuces in stock.........too plain-jane for me, I wanted this............