I agree with you, that they are my least favorite as well.
RUST RUST RUST.
Watch for rot in the sub frames and rear spring pockets, floor pans, where the rear quarters and rockerpanels meet, thats a bad spot. The front subframe mounts like to rot out. Rot in the lower cowl, you wont find that till you remove the fenders, the rear pan behind the bumper, under the wing on the deck lid, and sometimes around the windshield. Look at how bad the door hinges are, they wear and the door and striker gets torn up, You primarily need to look over the sub structure real good, everything else bolts on and is easily replaced, ie: hood, doors, fenders, and decklid. The newer the car, typicaly, the least rust.
1970-1973. 360hp LT-1 350 in the Z and the rare 375hp, 402-cu.in. L78 in the SS. M20, M21 and M22 four-speeds were also available until 1972--as were Turbo Hydra-Matic 350 and 400 automatics.
1977-'78, 15x7 wheels, the option of a Borg-Warner Super T-10 four-speed, 11-inch clutch, a stout drive shaft, 3.73:1 gear or 3.42:1 with an automatic
The original 350 and 396 cars have the most potential
Sagging door hinges are a common problem, as are body panel cracks in cars with T-tops. Leaking T-tops contribute to floor rot.
79 was the highest production year and would be more abundant. Your best bet might be 77-80. Not the fastest, but if you rebuild the engine, it doesn't really matter.