With a little work, the crossmember from '63 thru '87 will bolt in. '71 or later will have disc brakes. Make sure you get everything from the donor, including tie rod ends, center link, and idler arm.
Everyone has a different opinion, but most think the torsion bar susp. is superior to the coils. It was cheaper to put coils in, thats why GM scrapped the torsion bars. There are other benefits to torsion bars if you were planning to lower your front end in the future.
