Kinda tricky question,,, boils down to 4
The 409,396 the Pontiac 421, and the pontiac 68' 400 Ram air the ram air 400 had 390 STOCK hp's, The 421 ( not sure of the HP's) but the 62 Pontiac Catalina w/ the 421 WAS the fastest production car in the 1/4 mile, YES beat out the Hemi cuda and 62 corvette by less than .1 second ( define Production)... the 409 and the 396 ( oval ports) the 396 I believe had more HP's than cubic inches, so THAT maybe your answer, depends on what you ment. Of course we're talking PRE anti-smog.... Right?
NUTTZ