[leftybass209]

I've already been through this multiple times with my truck, and friends' trucks. The way you know for sure, is to measure with everything in place, suspension sitting where you want it (raised, lowered, bagged, whatever), on level ground. You can attempt to calculate the exact measurement you need, but a good driveshaft shop can take your measurement from yoke to yoke and calculate the distance needed for the slip yoke.