Small Block

Yeah that will lower the rear but the odd thing is the leaf spring perch angle (the flat pad on the axel that sets the pinion angle of the diff) is still different from a non FOM. So you will need to cut it off and re-weld it OR use a shim.
I know "hot rodding" is an art and not a science, so there is no set "kit" that will do this correctly. The problem is the same, you are only moving one side of the spring and therefore the perch is clocking and not just moving up. If just moving up (both ends of the spring going up at the same level) then the pinion angle of the rear diff only changes about 2-3degrees. Most people do not notice the difference and no real harm to the joint (however you should shim it correctly). But when only ONE moves, the pinion angle changes about 7-9deg causing the joint to bind and fail.

So with that said, if you know how to weld, just move the spring perch. You can buy new ones https://www.summitracing.com/parts/sum-720025 And then just weld them in when you get it set.

I don't think there is any difference if you use the FOM spring or new standard springs. I also don't think there is a difference if you change the rear shackle or just leave the FOM contraption in there. (I left it and think it may be a little noisy but not sure)

Hope that helps you out. I know I bought a ton of parts to do this and find the "best" solution.

 

not a FOM job, but shows the change in the angle of the pinion gear, how the shim corrects it and the need to shorten the drive shaft.

 

Hi,

a friend of mine has a F250 2wd from 1970 with FOM and we want to install a lowering kit with about 4-6"
at front as well rear axle. We don't want to notch the frame. If my understanding is correct you need to notch frame starting at 5" - so then our target
would be 4"

Do you have any recommendation in best case links where to buy e.g. I-beams, springs etc. for the front
We only find kits for F150 in the internet (e.g. DJM) .
We live in germany - so your support is really appreciated to start this project !
It is challenging to get information in germany and due to huge shipping costs we want to buy the correct parts.

In best case you can give us an installation guidance- this would be really perfect - it is my 1st work at a pick up with this kind of axle system.
Currently I am building a Cobra for me and in the past I restored some other historic cars... - now it's time to support my friend.


@Small-Block-850
Was your lowering succesful ? Can you please explain which parts you bought and how you managed it finally.

Rear axle:
@Pcmdub: Do you have photos of your shim or can explain what needs to be done to install the leaf spring perches from Summit ?

Front axle:
Any link / advice would be great how to lower it about 4-6"


Many thanks
Rouven

 

Rouven,

The spring perch is just the flat spot that is used to mount the spring to the axle. This perch has to be setup correctly to avoid angle issues with the driveline. (Search "pinion angle" for help on this). To set this up, you clamp the springs (be careful), remove the u-bolts (Get new ones) and brackets, cut off the factory perches with a grinder. Install your lowering setup, put the truck back down and set the correct pinion angle. Then weld the new perches onto the axle.

OR you can install the lowered shackles, put it on the ground, and measure how many degrees your rear axle differs from the transmission angle, and just install a shim,

If you have a "front axle" then this is 4WD? Not sure what you do in the front except cut the springs. If you have a 2WD, then you could use dropped beams or cut the springs.

 

Rouven, check out some of these:
Flyboy2610's DIY: Replacing King Pins & Bushings (LOTS of pics!)
Fatman Fabrications MII IFS Installation
Fatman Fabrications Bolt-on Axle Flip
DJM Suspension - Lowering I-beams & Components
FTE: AIM/DJM Lowering Thread
Bilstein Shocks & PN Info for Dentsides
FTE Thread: Chocko's 79 LWB F100
Airbagit.com Axle Flip Kit
Airbagit.com F250 Dropped I-Beams
Paul Horton's Welder Series - DIY Mustang II IFS Components
Mustang II IFS Kits
Jaguar XJ6 IFS Swap into an F-100
Team 321's 89-97 Cougar/T-bird/Lincoln MN-12 Independent Rear Suspension Kit
Team 321's 89-97 Cougar/T-bird/Lincoln IRS Installation Article
Fordification Thread: Spring Hanger Flip Pics
Fordification: Spring Hanger Flip - Pictorial
Fordification Thread: Spring Hanger Flip Shimming
Fordification Bumpside Thread: Details on Long Bed Pinion Angles After Full Spring Hanger Flip

 

Hi,

thanks for your reply. I understood function of spring perch and how to install it.
rear axle:
Buy the kit "DJM 4" Lowering Shackle Kit" - use existing FOM springs and adjust angle with new spring perch.

How about the front axle - it is 2WD:
Do have a link where to buy dropped beams for F250 ?
If dropped beam is not enough we can make small adjustment with cut of spring (even I don't like this so much).

Do we need new dampers or is the new range for dampers still OK ?

Can you recommend an online shop where we can buy new parts for a F250 - 1970.
We need mainly exterior parts, e.g. lights, reflectors, taillights glasses, chrome but also new door rubbers, dashboard-cover etc.
Everything that was burned by the sun...

Many thanks
Rouven

 

For the beams I suggest contacting DJM's tech or customer service. It seems to me that a while ago someone on here mentioned they did use the F100 dream beams on a F250. 1966/71 F100 and F250 both took the same king pin set. Ford part number C8TZ3111A. In 1972 they could be different.
As far as the parts go, I'd contact www.dennis-carpenter.com. A lot of their parts are made with the original Ford tooling. Also I suggest you go here. Read First:

Technical Info Hyperlink Compilation

Thread Rating: 2 votes, 5.00 average.MIKES 68 F100 on 09-07-2012
In it there is a lot of information. Including a bunch of sources for parts.