I can't seem to find a definite answer on whether I need flat or angled rear blocks. Some people say to use a flat block and shim down the carrier bearing, others say an angled block makes it so you don't need to shim anything. The truck is a 4-door long bed, and I want a 5" rear block if that matters.

 

Apparently every Truck can react differently, I recently put a ProComp 2.5 front / 2.0 rear Lift Kit in my 2006 F250.

I exchanged my rear OEM 2" Flat Blocks for some 4" Tapered Blocks (did drop Carrier Bearing a little too) & the truck developed a "shimmy" while accelerating. Long story short i was sure i needed Flat Blocks due to my new Pinion Angle & ProComp argued saying they needed to be Tapered. After i followed their suggestions & emailed them some Pic's, I finally got them to send me Flat Blocks which corrected my issue.

Here's my Pic's (remember your truck may react different) but i needed Flat-Blocks....

 

Yeah I can definitely tell that middle picture looks wrong. I actually have 4" flat blocks now with no issues, I just didn't know if I needed an angled block to go any bigger.

 

I put 5" flat icon blocks in my truck, and shimmed the carrier bearing down 1/4". Still vibrates a little but ive always heard a CCLB needs flat blocks

 

After installing the 8" lift on my 07, I was getting a bit of axel wrap on take-off. I installed a set of ladder-bars and no more problems. My block are not tapered.

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Ok so it looks like flat blocks are the way to go. Thanks guys

 

Man i want a set of Traction-Bar's one of these day's
Yeap Flat it is, amazes me that everyone here that answered has Flat's & ProComp acted like my truck needing Flat's was a fluke....
WTF ProComp