How much lift can you go without lengthening the drive shafts? I'll be installing 1 ton springs on friday and don't know if i'll need new shafts. It's an '81 4x4.

 

4"s is about max b4 the front needs to be lengthened

 

Yes, 3-4" is about the max lift on the front, depending on how much flex the springs have. I was OK with the stock shaft and 3.5" lift, but when I reworked the suspension for more travel, I found I needed to lengthen the front shaft. Usually you'll run out of the relatively short stock slip yoke length before the actual shaft length is an issue (i.e the shaft will separate under full droop).