Flat Carts - Lear Jet Paks
Well I guess I didn't buy many of these because the pinch rollers were always melted. Now I wish I had. I only have ten. The best two are Otis Redding - Dictionary of Soul and The Best of the Lovin' Spoonful. I have been repairing the pinch rollers today. I replaced them with plastic ones I culled from my dupes heap. The rubber ones in the newer tapes aren't wide enough. These "flat packs" are the Lear Jet Pak 8 cart shells. They were only used in '66-'68 or thereabouts. I have some old catalogs from those days and in '67 the newer shells were already showing up. Here's a sample jet pak I found on ebay:

I repaired several good carts. The Blues Magoos, Chad Mitchell, and Songs Made Famous by Hank WIlliams played by the Modern Sound. It says modern rock acid on it. Get it right, Gramps! It's acid rock. Cheezus! They don't really do much to Hank's tunes either. Just use an electric guitar, but it is cool.