When did the 426-4v Hemi & 427-4v HiRiser become legal?

DeuceCoupe · 05-22-2023, 11:05 PM

I know these combos appear in the NHRA guides today:
426-4v Race Hemi Mopar
427-4v HiRiser Ford (1964)

But to my knowledge the combos never existed outside of NASCAR.

Were these combos NHRA legal in the 1964-1971 era, and did anybody run them? If so what were they factored at back then?
(Near as I can figure, the Race Hemi & 427HiRiser-8v were factored at 500hp, except the 427HiRiser-8v was factored down to 450hp for its final legal year of 1969).

Does anybody run the 4v combos today?

05-22-2023, 11:05 PM	#1
DeuceCoupe Member Join Date: Feb 2016 Posts: 267 Likes: 96 Liked 45 Times in 41 Posts	When did the 426-4v Hemi & 427-4v HiRiser become legal? I know these combos appear in the NHRA guides today: 426-4v Race Hemi Mopar 427-4v HiRiser Ford (1964) But to my knowledge the combos never existed outside of NASCAR. Were these combos NHRA legal in the 1964-1971 era, and did anybody run them? If so what were they factored at back then? (Near as I can figure, the Race Hemi & 427HiRiser-8v were factored at 500hp, except the 427HiRiser-8v was factored down to 450hp for its final legal year of 1969). Does anybody run the 4v combos today?