You could put an LS-3 with the front drive distributor from PACE Performance if want a lot of horsepower in an all aluminum package.
Just change the valve covers to something vintage looking or generic and most folks will wonder: What kind of Ford motor is that?
GMP-19301360-CHX - Pace LS3 550HP Carbureted with HEI & As Cast Valve Covers.
It will fit on the mounts with minimal modifications.