Boss 351 Maverick
455 Stage 1 Omega
RamAirV '73 GTO
SOHC Mustang, Maverick or
Boss 429 '70 Falcon
ZL-1 '69 Chevelle
RamAir IV or V Pontiac Astre
'70 Hemi Duster
440 Duster/Demon with Max-wedge top-end
These are all easily buildable with pretty much factory parts.
Randall AMC in Mesa,Az. built 401 Gremlins & even a few 401 Pacers!
Baldwin/Motion built a few big-block Vegas & would build/sell most anything you could imagine. Mr. Norm's pretty much did the same thing in Chicago. Unfortunately the other dealers didn't see fit to do this with their marques, but I'll bet Tasca Ford had a few oddball cars running around.....