I've had my affair with FMJs. Unless you buy in nice, you'll be throwing money at a car with no support.

I'm currently in a Late-B car. Solid support for mechanical parts, but again, buy in nice or you'll find that parts (panels, interior, etc.) don't exist.

If I was starting from scratch again, I'd go either 1971-74 B-body or a Duster/Demon. Plenty of aftermarket support. Plenty of parts. Plenty of options.