whitey382

In advance I would like to point out that I'm new to the forum, so go easy on me. I searched the forum for my specific question and didn't see anything so here goes.....

I have an 08 F150 2wd. I got the 6" Fabtech suspension lift with the stock spring coils in the front and blocks in the back. Due to some warranty issues I had them add a 5/8" spacer at the rear of the drive shaft between the driveshaft and the rear diff. The rear of the truck sits lower (by a couple inches) as most of you probably know. I was searching around and see a lot of guys do the larger blocks in the back to compensate and level. So my question is 2 fold.

First, does anyone know of any negative side effects of going with a 4-5" block in the rear?

Second, if i go with this set up, or even a leaf spring set up that lifts the rear up to level, is the drive shaft angle or length going to change enough that I will have to do work to the driveshaft? (keep in mind I have the 5/8" spacer on the back of the driveshaft)

Any help would be greatly appreciated, thanks guys!!!!!

whitey382

i've continued to search around the forum and it looks as though some of the guys with larger lifts have angled the rear diff so the pinion points up more, helping reduce the angle on the drive shaft. What's it take to angle the rear diff up?

thump

What sized blocks do you have with your current setup? Are they stacked with the factory block?

I had a stacked 2.5" procomp block plus the 2" factory blocks on the rear, just recently switched them out for the single 5" fabtech blocks with the built-in replacement bump stop. No driveshaft issues.

With the wheelbase length of these trucks I think you'd have to get a pretty extreme lift to have issues with driveline. A couple extra inches of lift barely changes the angles with a 5' driveshaft. Typically this is more of an issue in shorter vehicles like jeeps.

whitey382

so the blocks that I currently have are the 2.5", it looks like the front is currently 2 1/4" higher than the back, so 2.5" blocks should take care of it. where did you get the 5" fabtech blocks from and how much did you pay? have you ever done any towing with your set up? does it do fine with the 5" blocks? have you ever gotten underneath and looked at the yolk going into the tranny? is it sticking out any further than stock? any vibrations or anything while driving?

sorry for the million questions, just trying to get all the facts

whitey382

sorry, i wrote that 2.5" blocks would take care of it, I meant the 5" blocks, they are just 2.5" bigger than what I have is what that comment was meant to say

thump

I just reread your first post mentioning you have a 2wd - that's why your rear is low. The 4wd F150's come with a 2" factory block that includes bumpstops, so when you add the usual 2.5" block from a procomp or fabtech 6" lift then you'll have 4.5" worth of blocks on the rear and it all evens out.

A quick google search for the "Fabtech FTSBK52" 5 inch blocks should get you what you need (I got mine through my local 4WP). You'll likely also want the u-bolt kit as well. There's some pics in the thread here: https://www.f150forum.com/f4/procomp-upgrade-kit-56803/

I have zero driveshaft issues, but mine is an FX4 so I don't know if there's any difference in the stock driveshafts (your Ford dealer's parts dept would probably know). I tow pretty regularly and have never had anything loosen or shift (and that's with a locker and 37's).

whitey382

thats freakin beautiful, just the kind of information I was looking to hear. did you also purchase the shocks that are available with the 5" blocks or did you just use the existing shocks your kit came with? mathematically I would have an extra 2.5" of travel to account for, not sure if the current fabtech shocks are good for it.

thump

Glad I could help. My shocks are the ones that came with the 6" Stage 1 Procomp kit for the 4x4 F150. I didn't change anything when I moved to the 5" Fabtech blocks because it was only a 1/2" change from the stacked blocks I had in there already. I would guess the ones that came with your Fabtech kit should be okay, but you can always call them and check.

whitey382

Has anyone used the 6" fabtech lift with the 5" fabtech rear blocks, or perhaps the pro comp 4" rear blocks on a 2wd? I called fabtech and they said they had never used the 5" rear block with the 6" lift. He also said that measuring the height of the truck at the wheel wells isn't accurate because the wheel wells are different sizes. Thump, you got any more insight into the situation? or anyone else would be much appreciated.

thump

It more about aesthetics than anything. In my case I wanted the rear to be a touch taller and wanted to get rid of the stacked blocks so I measured the current height of the stacked blocks (2" factory block + 2.5" procomp block = 4.5") and went for the 5". My truck was already level with the 4.5" setup (you could set a level on the bed rail and it was nearly even) but because the front wheelwell is taller it made the truck look taller the in the front to me sometimes, and when I put any weight in the bed it would would only worsen. Adding .5" only changed a hair, which is good because I didn't want to buy new shocks or u-bolts, but I'm also adding airbags (because I hate the pre-runner look I get when towing) as soon as I get a chance to get them off my office floor and installed, which will likely make it sit another .5" higher when unloaded.

I'm not sure why the Fabtech guy isn't familiar with this. I think Larryw1 is running a procomp stage 2 with the 5" fabtech block as well, plus a procomp AAL on the rear.

If you really want to get scientific about this then find some level ground and measure your rear wheelwell spacing from the top of the tire. Then using a tall jack, jack the rear of the truck up by the frame* until it gets to the height you want it visually and then remeasure. This will tell you how much additional block spacing you need from what you have now to what you want. If your rear tires start to lift off before you get to the height you want then it'll also tell you that you need longer shocks.

* I take no responsibility for damages from improper jack technique here