I’m looking to put a 4 inch front lift and 2 inch blocks in the rear of my ‘81 f100 2wd, but I’ve had people tell me that it creates a problem with the I beams. I’ve found a fabrication shop that makes the I beams up to ‘79 and I was wondering if those parts would work on my ‘81? If anyone has answers or other recommendations on how to achieve the lift on stock I beams that would be much appreciated.

 

Most of the time you do a lift to get ground clearance.
Thing is with the beams and any new trucks with IFS you dont really get it.
To get the front suspension back to factory spec you need drop brackets for all the pivot points so you need to lower them loosing ground clearance.

Ok yes you can get a little back by running larger tires but you just spent $xxxx's for a lift that you did not get then need to spend more $xxxx's for wheels & tires to get a little lift of what 2 or 3 inches? For what a look to crush cups in a parking lot?

If racing off road you dont want ground clearance, keep the truck as low as you can, but suspension travel.
A 2 inch lift is about what you want as it will add more travel and keep the truck low.
Just my .02 and yes I have raced Jeeps off road. 10 trucks on a Moto-X track for 10 laps over jumps and all.
Dave ----

 

Mainly want the lift for the look and to clear bigger tires. If possible I’d like to avoid modifying the I beams at all by possibly doing just a level but I’m out of my element when it comes to this stuff

 

Anything more than a 2 inch lift or lowering runs into issues trying to get the front suspension back to factory spec.
The other issue YOU run into is the 80 to 82 tF100's and maybe the F150's use kingpins and on the F100's there are 2 different sizes.
They ONLY way to bring the front suspension back into factory spec is to bend the beams and there is no shops that do this now days so you would have to hit a big truck repair and see if they can bend the beams.

Now on 4x4's they use drop brackets when lifting but I dont know if they will work on a 4x2 truck or not?
The 100's and 150's use coil springs up front on the 4x4's and from what I see posted you can swap the 4x4 stuff into a 4x2 truck as it is a bolt in.
So if you get the drop brackets for a 4x4 with the lift you want all that should fit your 4x2 based on what has been posted but you are on your own as I dont remember anyone doing this, lifting a 4x2 truck or using 4x4 parts.

Also note the rear springs are wider on a 4x4 so lift blocks for a 4x4 may not work there.
Front would be coils and maybe spacers to get the lift and thinking should work but .......

Oh do you have the wheels / tires yet?
If not you will want to check the wheel bolt pattern as the 100's also used 2 different patterns 4.5 x 5 (car size) and 5 x 5
Dont ask how I know this and no I did not buy wheels / tires.
BTW I have found that F100's with power brakes have the small wheel pattern and small kingpins.
F100's with non-power brakes have the large wheel pattern and large kingpins.
But do check to see if yours follows this pattern before ordering parts.

Good luck and keep us posted so it can help others.
Dave ----

 

They make lifts for 2wd trucks. Here is one in this link. https://bds-suspension.com/products/...f150-80-96-2wd

If you plug in your 1981 f100 2wd you will find it doesn't fit. But if you plug in a 1981 f150 2wd it will say it fits. It will fit any 80-up f150, but not the f100's. All you have to do is go to the junkyard or buy a donor f150. Swap out the front suspension out of your f100 and put the f150 suspension in place with the lift kit at the same time. The f150 suspension will bolt in to your f100.

What size wheel pattern does your truck have? Some f100's had the car pattern 5 on 41/2. The f150 has a 5 on 5 1/2 pattern. So if you do the f150 swap, there is a chance you will need new wheels if you have the small pattern. And you might want to change out the rearend to make those rims match the front if they are different.