Thing is, if you get something from the late 70s with 4 doors, it's not "cool" and you can score a solid one one for $2k. People thumb their noses because stock, a 300 ci V8 only got 130 hp off the showroom floor.
All the smog stuff can be ripped out. Lean burn carbs and distributors can be replaced with non feedback holleys and vacuum advance units. Cams swap out. Heads shave. Catalytic convertors don't strangle much but a dual exhaust with requisite glasspacks might fit and can be pretty cheap.
I would honestly get someone else's project. My BIL bought a crown vic, did a whole new front end, had the transmission rebuilt, fixed the airbag light, used cop grade stuff, then got tired of it and sold it for $1000. Couldn't find any other buyers bc of gas prices.