unbolt your U bolts jack up the back of the truck but the blocks in set the truck back down on the rear end and install longer U bolts, and you probley need new shocks with a 3" block im not sure though.
if you can (or know someone that can) cut and weld you could cut off your shakle hangers and flip them and weld back on...you'd get about the same ammount of lift, and wouldnt have as much axle wrap problems as you would with lift blocks. that would mean more power to the ground rather than spent spreading your spring pack out then snapping it back together...not good for parts staying unbroken. :imo
Dont the NBS have 2" lift blocks from the factory? If you just took out the 2s and put in 3s i dont think youll need new shocks. DO NOT stack blocks, it is trouble waiting to happen, ive personally witnessed them slip out and a truck hit the floor.
I had 4" lift blocks on my '85 gmc, and i ran them for months and never had problems... then one time i opened my 454 up and i heard a small clunk didnt think anything of it....bout a week later i was down there greasing u-joints and the rear blocks were 1/2 way spit out ow:
It was partially my fault, i didnt torque up the u-bolts like i should have.. but i will never run more then about a 4" block and i keep a good eye on them.
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