There is nothing wrong with a Muncie trans especially the M-22. I assume you know how to shift. I've had a few of them and never replaced a clutch, transmission part, anything. You just have to know what you are doing.
Me either. I put 1/4 million miles on an M-21 and never opened the thing up.
I'm a Mopar deep down, but I will give credit where credit is due. Nothing wrong with GM..... or Ford for that matter. I like muscle cars from all 3 makers.