What size clutch: 72 350 with a three speed 1/2 ton
 

I want to buy before I pull the tranny. Any tips. never done this before

Re: What size clutch: 72 350 with a three speed 1/2 ton
 

Should be the 11" clutch. They came 10", 11" and 12". Make sure you get the clutch disc centering tool. It should come with the kit if you buy the clutch and pressure plate. Eyeballing the disk dead on in the center is not easy to do.
The rest is a simple job. Your first time will probably be frustrating, but any you do after this one will be easier.....