Whole lotta work and it wont be easy. You'll need:
Clutch Peddle Assm.
Cut a hole on the tunnel
There is a difference between auto and manual tran drive shafts. Trucks equipped with manual trans had a large diameter drive-shaft than the auto. NV3500 manual trans is a one piece aluminum trans used on half ton trucks. You can use a NV4500 manual trans from a 3\4 ton truck, good luck trying to find either one. Manual trucks are somewhat rare. Not a lot were produced so locating necessary parts and peddle assm is going to be tough.
Keep it Mopar, buy Mopar Parts.
I am completely disgusted every time I think about having to take a distributor cap off of one of these trucks -Screamintrashcan