My 71 , for a number of years, had a 694 CID Merlin V8 in it, backed by a Richmond 6 speed.
I put the original 455 HO back in it a few years ago, although it has been bored and stroked to 494 CID and had the compression raised to 13.5:1. Reworked Holey Dominator now flows 1350 CFM, up 200 from its original 1150, sitting on the original high rise aluminum intake. Isky roller cam and rockers, studded the heads down, Venolia slugs and rods, Hank the Crank crankshaft, Milodon oil pump, larger pan, sodium filled titanium valves with stellite faces, Hooker super comp headers. Also went back to a Doug Nash 5 speed for it that I had in it after removing the M22 decades ago. Still have all original parts so it could be put back to completely original (well, except for the being bored that is). Needs to be painted, was garaged all its life, but I used to run it (with the 694 Merlin and 6 speed) in the original Silver State 100 road challenge, so it has a few scratches here and there from dust and dirt at high speeds.
Took the roll cage out awhile back, put back in the original seats, and new carpet, need to recover the seats and reinstall the original console one of these days, could probably stand a new head liner too, there is one small tear about an inch long over the clip for the shoulder harness on the passenger side, other wise interior is pretty near mint.
Body's paint is pretty good, it's the fender skirts, front spoiler, and flares (white) that show the paint chips the worst.
Doesn't like to run on less than 110 octane gas, but it pulls really strong through all 5 gears even with the 3.08's I currently have in the differential. I only drive it when the weather is nice around here, and not too hot, as it only has 2-160 air..... two windows down and 160 MPH if you want cool air flowing!