The rears are usually easier to find at swap meets. I picked up a really nice pair of green ones at the Nast last year for $10 a pair. It's the metal that is usually rusty.

68 Road Runner (383/4speed, post car w/decor pkg) - Major Project
69 Road Runner w/472 Hemi & 4 speed.
70 Challenger R/T SE EF8 w/ V9J, U - A32 - Major Project
2023 Ford Mach 1