if i were you i would buy a donor 5.0 car the 4cyl brake will work yes but the factory 5.0 stuff is better and bigger it all depends on how good you want to stop
No the rear end will no fit its an 8.8 technically but its got different mounts and i think the vans use leaf springs it would be easier/cheaper to guy a used 8.8 out of a mustang
no idea on the tranny im sure you could make it work but who knows as for the rest of the stuff prob not
find a 87-92 5.0 ho and start out with that better heads and forged pistons and whatnot man
I would be willing to lend a hand tho