You may be able to get away with running a regular driveshaft in the back, although 12" is pushing it. Getting your angles equal at the t-case and the diff is extremely important. Here's how I did mine- I installed everything with the the stock perches in place. I made lots of measurements and figured the difference in degrees that the new perches would need to be welded on to match the t-case angle. In my case, it was about 23 degrees on both sides IIRC and my truck has zero vibes from the driveshaft. It's really just a lot of trial and error and I was fortunate enough to get it right the first time. Keep in mind, your probably gonna have to run 1410's at both ends= more $. If you haven't checked out the driveshaft 101, give it a shot. Good luck!