The closed driveline is easy to fix - just get a 55.2-59 rear "pumpkin" from the same sized truck and swap it out, then have a driveshaft made to fit.
Is this a 1/2 ton or a 3/4 / 1-ton?
The clutch and brake pedals don't bolt to the engine, they attach to a crossmember under the floor. I fully intend to use them in my 250/NV4500 swap.
The forums at
www.oldgmctrucks.com are a great source of GMC info.
