Same swap in an F body. Driveshaft never cut. You may need to change the yoke on the dif or use a U-joint that has the two sizes on it. I found one at the local parts house. To do it correctly, the joint end needs to be changed, if you do that, have them knock the half inch off for peace of mind. You never know when you may hit something in the road and send the yoke slamming into the transmission tearing things up.