I'm in the process of installing a 05 town car IFS in my 54 f100. I have the crossmember in and center but had a question about the rear lower control arm mounts.

I have looked and can not find any good pics or info on what everyone did for the rear lower control arm mounts. Did you make the mounts off the side of the frame, or did you put a plate under the frame for the mount?

If anyone could share what they did and post some detailed pics. Thanks in advance, Jason

 

what rear end are you going with ?

 

Umm? I have a Mark VIII IRS going in the rear but not sure why that matters? I'm just looking for info on finishing up the front suspension

 

Here's a couple of pics I took of a 2004 Crown Vic lower A-arm on the car...after researching the geometry I opted not to go with this setup so I don't have any pics of it in a truck. Hopefully these pics might help in visualizing how they are mounted on the car.

 

Thanks for the pics, But I already know how they mount in the crown vic. I need pics of them mounted in a 53-56 F100 So I can fab up some brackets and then get working on installing My 4.6 DOHC cobra motor

 

There was a old article on FTE about a 67 F100 installing a 2006 cv ifs. It started on 3-04-2008 and ended on 8-23-11. He does cover your questions. There were many, many pages covering all aspects of the install plus other ideas about tires etc. THERE IS A SEARCH FUNCTION AT THE TOP OF THE PAGE OR YOU CAN SELECT PAGE NUMBERS AT THE BOTTOM RIGHT OF THE PAGE AND GO BACK TO THE BEGINNING OR THE END DATES AND BOTH WILL HAVE THE COMPLETE ARTICLE. CHUCK

PS: If I remember correctly he made a plate and attached it to the borrom of the frame.

 

Charlie,

You said after researching the geometry, you decided not to go with this option. Can you enlighten us on the geometry issues? I don't see why it would be different than in the car, unless the angle of the frame affects the caster.

 

When I said geometry I am referring to the track width of these front ends. There has been a lot of discussion regarding the Crown Vic IFS...those who have invested the time and $$ are more than willing to defend their choice. I don't care to get into a pi$$ing contest with anyone regarding this install. When this option first came to light I went to a wrecking yard and took many pictures and measurements and determined that the track width of these front ends were far too wide to use on a 53-56 F100. Attached is a drawing I made with my measurements, as you can see there is 18 inches from the mid point of the frame to the mounting flange on the rotor. Add up this distance on both sides and add in the distance between and you get 18+33+18 which totals up to 69 inches. Take a measurement of your 53-56 F100 from inside fender lip to inside fender lip and see how much room there is for a wheel and tire. I don't recall the exact measurement off the top of my head but I believe it to be in the neighborhood of 74 inches. Using 74 as the inner fender width, you would have 2.5 inches from the mounting flange on the rotor to the inner lip of the fender...not much room for wheel offset and tire bulge. Not to mention what happens when you turn a corner.
Yeah I know that you can buy a Crown Vic IFS for not much money and yeah I know that the crossmember will fit nicely between the F100 frame rails...but if the geometry (read, track width) is too wide then how much of a deal are these suspensions?

 

I put the CV IFS under a '70. The mounts you speak of are under the frame just forward of the cab mount on a bump. I let the control arm sit naturally and the CV bushing plate touched the frame at the rear. I used 1/8" and cut a plate to match the top of the CV bushing plate. The front was 3/4" below the frame so I cut a piece the width of the frame 3/4" wide. Ran a bead across the back of the plate I made to the frame. Weld the 3/4" piece in place at the front. Cut a triangle piece (like a gusset) and ran it on the outside of the frame & to the top of the plate I made. I know I have a pic somewhere but can't find it right now.

Clear as mud yet? As to the track width you run wheels with the tire on the inside instead of the outside. I am very happy with the swap. I am also doing a TBird IRS. Hopefully this coming weekend. Are you going to use the mount kit from truckirs.com?

 

The 1970 model F100 has a considerably wider track than the 53-56...I don't have the specific numbers but the extra width makes this IFS installation more feasible.

 

I am showing the CV track width as 63.5 and the 56 F100 as 59. So that makes 2.25" per side out from the original location of wheel mounting. The wheels push that 2.25" inside the wheel well. Here is my truck and if you look at the front wheels you will see what I am saying. Yes I am pretty sure I have to give up any kind of deep dish wheel showing on the outside but I can still go 10" wide just all on the inside.

 

Just remember where the track width is measured...if you measure the CV track width, you are measuring to the center of the tire. That is a tire that is mounted on a wheel that has a significant positive offset. Your truck demonstrates this fact as can be seen by the flat appearance of the front wheel especially in comparison to the rear wheel. According to the book I have read, the track width of a 1970 F100 is 64.4 inches. So you have 5.4 inches more to work with than a 56 F100 and are still limited to what rim you can run. I am not judging what you have done...what I am saying is that anyone who is considering this particular IFS for their early F100 should be aware of all the issues before they make a decision.

 

If memory serves me right I was looking at a 1/4" difference each side. But again that is track width not hub to hub. I am not doubting there may be a differnece but when it all boils down to it for the most part full size vehicles have the same overall width thus in theory should have the same amount of room for axle width. I think Chrysler was the first to move the hub outward yet the vehicle width remained the same.

As a demonstration of difference between track width and hub to hub I think my wheels show it very well. The rear wheels are 10" wide with centered mounting. So 5" outward. I am not looking at the truck right this minute but I believe the appearance of the front being wider (outside edge of the wheel) is true. With all that being said I go back to your drawing indicating a 5" difference which may not be all that far off. But again a 5" difference in the '53-'56 looks to be about the same as my truck.

I will try to get a measurement hub to hub on the TBird IRS if I remember to do so when I install. May prove helpful to others. Moving the hub outward is supposed to give the vehicle more stability. I know the old buckboard feel is long gone in my truck even with the leaf sprung 9" out back with no sway bar. Along with all of this you must run wheels that are a min of 16" to clear the calipers. Most recommend 17" unless you are using the CV wheels which are special 16" wheels as I understand it.

 

Got a pic of my rear mount. I am not building a show truck just a decent driver so I didn't put much effort into beauty.




I also used the spacers from the CV. Cut to fit inside the rails and used the remainder on top of the rail. The piece on top of my rail has a threaded nut.