8 Track tape thingys
My high school graduation present back in '69 was having a Motorola 8-track player installed in my '66 A100.
Later on I put a Pioneer Supertuner FM/8-track with a Craig poweramp and 4 6X9s in my '74 B300, hot stuff at the time. I have a lot of good memories of cruising around delivering pizzas with the tape player cranked up playing Led Zep, Pink Floyd, Robin Trower, Hendrix, Doobies, J. Geils, Allman Bros, and on and on.
I believe that Bill Lear of Learjet fame is the inventor of the 8-track player.
I remember the matchbook trick too. Something else that helped sometimes was cocking the tape sideways to load or unload pressure on the drivewheel.