Had a few but two I wish I still had are a 67 Olds Cutlass convertible w/factory 4spd and a 65 Plymouth Sport Fury.
The one I wish I never bought:77 Ford Mustang II with the Cobra package. 302 4spd. Black/gold. Bought it new and the engine rattled from day one. Dealer said there was no problem. Took it to another dealer and they said whoever built it must have been drunk. Completly rebuilt and balanced. Cost me $50. Then the transmission synchros started going. Had electrical problems. Stripes started peeling. Lots of other stuff. Had it 9 months. I let it get repo'd.
Indeed the 1970's and 80's were very dark days for Detroit- all cars and most trucks were an incredible P.O.S., and I thought it was all over for American vehicles. But the Japanese gave us the competition we needed to build decent quality cars and bikes again. These days will be known as the high water mark for internal combustion engines and American ingenuity.