Found manual transmission parts, advice needed

Hey guys, I've been looking to switch my '72 dart over to a four speed. I've asked everyone I know, and finally found a guy here in town who's an old drag racer, so I called him and he told me to come over and we'd find out what he has. So I go over there today, and he opens the garage doors and I about hit the ground. The first thing I see is a '68 hemi barracuda drag car, behind it is a all original '69 hemi roadrunner, in the back on racks are two more hemi barracuda drag cars. so he goes looking around in all his parts and finds a floor hump, a bellhousing, flywheel, clutch, pressure plate, and a 3 speed transmission. he says he has all the linkage around there somewhere, he'd find it and give me a call when he has it all together. He says he wants to sell it all together, and wants $250 for everything, and that I could probably sell the 3 speed for a hundred bucks or so and find a four speed for not too much more.

I definitely think all the parts are worth it, how hard is it going to be to sell the three speed transmission? And I assume I'm going to need another driveshaft yoke, and will I have to shorten the driveshaft? My car currently has a 904 in it. Will the crossmember be the same?

Thanks guys!
Luke