hi Matt i had a 51 F1 that i put a 77 ltd clip[rearsteer] under and had lots of room under the hood for a 429. it must have caused some talk cause once even a cop was asking me if the truck really had a bigblock in it , and if it ran pretty good. i could go 80 with 1 finger on the steering wheel, first timers luck maybe. but gas waz cheeper 16 yrs ago. i have a 49 F1 now and i think it will get a 302 or maybe a granada 6 as i get there. besides u could sell that 312 to some rat rodder for good money. Ives Bradley rdhotfrd