I don't know 71-up B-bodies well, but I've used ACC on about a dozen '68-'70 Bs & '70-up Dusters, never had a problem.
Soon as I get it, I lay it out either in the car or on the guest bed to let it flatten out.
Installation: on the Bs I locate the carpet at the gas pedal/heel pad 1st, double-checking everything.
After the heel pad, I like to go next to the seatbelt anchors.