u- joints
Similar info to what Demonracer said. My driveline guy said that Spicer solid joints are the best. so I use their 7260 version in my Dart with one of his driveshafts. I suggest a billet steel rear end yoke because the OEM style can spread over time and heavy abuse. My Dart weighs a minimum of 3,530 lbs. That's how I lost a driveshaft many years ago and it shattered the trans, bent the converter and knocked pieces out of the back of the block. No problems since.