I don't think it would be that hard to get 400 FWHP out of a 289. My 302 with 9.5:1 comp, ported '70 351W heads, HO cam, headers and a 4 bbl will do around 340 FWHP. Now, granted, I did get that number from engine analyzer (which is reputed to be fairly accurate), but with aluminum heads, a...