In my search for longer U-bolts I got a email response from performance lifts saying they don't stack blocks so they don't have long U-bolts. I just asked for U-bolts for adding a 4" AAL for my current setup. I'm not adding any blocks here.

So my question is, if they consider using a lift kit block on top of a bump stop block as stacking, how do they install lifts on a FX4? Are bumps stops are technically a block? When we installed my lift EDIT we put the bump stop ON TOP of the lift block.

So did everyone remove the factory 2" bump stop and just use that little block the lift kit has? I don't think so as the prerunner look isn't that bad across these boards.

Input?

 

Are your U Bolts that close to the end of the threads?

 

the lift block goes under you stock block with bump stop arm. The way you have it you have no bump stop and that is killer on your leafs as well as possiably unsafe, if you over load your truck you wont be riding on your bumps youll just be negative arching your leafs causing weird and dengerous handling.

 

Ethan, if hes only adding a 4" leaf pack than he won't need longer U Bolts for that. Correct?

 

I have about 1.5" of thread left on them.

right. I type that out of order. I have them installed correctly. I wonder why performance lifts was calling that stacking blocks. Maybe the are just mistakening my lingo there.

damn call me stoopid. I didn't think in terms of a spring. The leaf spring would be curved to give 4" of lift it wouldn't be a 4" stack of springs. duh.

 

Most lift kits will give you a taller block to replace the factory blocks. Fabtech's 5" replaces the 2" and the 4x2's have no block so they just go in there (If they wanted you to double stack they wouldn't put the bump stop beak on there). So, if you put a lift block under your factory block then you double stacked. This is why about everyone on here has an add a leaf or the 4x2's put on the 5" fabtech block to get away from the prerunner look. Anyways, you shouldn't need longer u bolts with just an add a leaf because the typical add a leaf is between .323 and .360" thick with the exception of the short add a leafs which are typically thicker. If for whatever reason you need longer u bolts you can pick them up from Atlas which should be pretty close to you down in Wichita.

 

NO!! do not stack blocks! EVER!!! period. They give you the lift block WITH a bump stop (if its a quality company, if not then don't use it). You are suppose to swap your factory lift block (of 2" or so) for the new 3" or 5" (or whatever ") . Its a REPLACEMENT block.

P.S. fx4 isn't the only F150 with factory lift blocks out back. All 4x4 have em

 

Ok this is what came with my Pro Comp Stage I lift. The "beak" is my factory bump stop. Pardon the nasty it's winter here.

The

fabtech 5" block don't have this "beak" either. This is the image on performance lifts. Maybe this image is incorrect? I think I'll create a thread begging for pics of the 5" block.

 

The fabtech block does have the beak on it for sure so the image you have is not accurate. A lot of pro comp kits will stack blocks which shouldn't be done but if the u bolts are properly torqued you shouldn't have any issues. If it were my truck and I did a block then it would be a fabtech 5" because it's made of steel unlike the pro comp aluminum and it's not double stacked. It would also be better if they gave you a bump stop extension so you could put the beak on the bottom and take some of the pressure off of the double stacked aluminum block when loaded.

 

^^^ notice the little red note in the corner saying that the picture may not be exact to your model. This mean they probably take one picture and use it as a universal picture. A lot of internet companies will do this to cut corners. My 3" lift block had the "beak" or bumpstop. I am sure the 5" block will also have the bumpstop. Just called up my buddy Mark (work at Fabtech) and asked him to verify and yes the Fabtech 5" lift block DOES come with the "beak" or bumpstop.

P.S. no offense but yet again Pro-Crap has surprised me...

 

Yea I noticed that red type after I posted. I'll just drop the $50 and order some fabtech block now from performance lifts. Then pull out the factory and pro comp blocks and swapping in the 5 incher. I shouldn't need any U-bolts then since it's a exact size swap. Then I'm only adding a leaf in there for the 4". I'll keep you all posted on the install or annoyed with more silly questions.

 

I dont see any problem with stacking blocks on our truck. We use a 2 pin block that way they cant twist apart and more sheer strenght. On other trucks with single or no pin blocks no way but our two pin makes it fine.

Note when I say stacking I mean like stock block and then the procomp block. Not 3 or 4, 2 inch blocks and really any rear lift over 6 inches needs new leafs a 6 inch block or more is crazy.

 

yes anything over 6 will be axle wrap central

 

Extremeethan: i would agree with you that with our 2 pin style blocks it is "more" acceptable to stack and you wont have (as bad) of a twisting motion. But ask anyone who has stacked before, your ride goes down the tubes and you will have bad axle hop/wrap. On top of that, in all honesty, it just looks cheap and crappy. Just my opinion on the last part. And if your just going to pound pavement then the stacked blocks will seem fine.

Impact9: Awesome to hear it man. i am glad your going to just go for it and get the Fabtech lift blocks. You will be MUCH happier in the end. Like kansasjoe said: Pro-Crap's blocks are (flippin) aluminum, and Fabtech is steel. For that reason ALONE i would go with em. Oh and ask away! I will be happy to help you out with any questions (if I can)

 

I have the procomp aluminum blocks under my stock block and no one can say I dont beat my truck. Out of all the parts on my truck I worry about my rear block set up less then anything.