i building a truck from the ground up. engine swap, 5.29 gears, aussi lockers front and rear, custom flat bed, 4in pro comp lift, 2in lift shackles and 35 in tires. im a few weeks from having it done but im wondering if im going to have to lengthen my drivelines with the 4in lift and the 2in lift shackles? anybody done this before and have any input?

 

Not sure on the 1st gen but I did a stage II Pro Comp 4" on my 2nd gen and it worked fine without any drive line lengths but you may have to clearance a bit off your gas tank cover other then that it was a bolt up and play set up for my 2nd gen.

 

It's fine with a 4". Over 5" and it would be a good idea if you use it offroad and flex it.

 

A lot depends on the type of lift spring. When I put on an off the shelf 3.5" lift spring, I had no issues with drive shaft length. But when I reworked the springs for more flex and especially when I moved the front axle forward about 3/4", I had to get the front shaft lengthened. A drive shaft spacer is always an option if you need to make the shaft just a little longer:
- http://www.4crawler.com/4x4/ForSale/...ftSpacer.shtml

 

I have that same lift down to the shackles and I have never had issues with the drive lines.