I have a fatman ultra low mustang II weld in IFS. I have everything down to the frame, body off and I got rid of the original front already to save space in the garage. Does anyone know the centerline measurement on the frame for the front to get it centered back in the wheel well? I know the wheel base is 115 inches, but I installed a 56 rear and posies springs which center the wheel in the wheel well better than stock. I do have the U brackets still on the front outside of the frame. Any help would be appreciated. Thanks
I called fatman and the general rule is to use the area at the rear 3/8 hole of the V bracket on the frame for the center. The person I talked to was Mike at fatman who also said they have gone by that on certain cars and had to cut everything out and re-weld again. I will tack everything together and install fenders temporarily to check before welding out.
On the heidts web site they have instructions with diagrams that show the centerline 16" from the center of the front bumper mounting hole. this is how I mesured mine.
too late for you now but for others reading this you should mark the centerline before you remove the front suspension. I did mine with a stick on 2 ladders and a couple plumb bobs. marked the centerline with a hacksaw so it would not disappear. it is also recommended that you tack it all in and install the fender to see that it all lines up
Even marking center line is not enough, to much riding on it to be accurate. When you put the lower MII on the car/truck will nose over. I always mock up the front fenders to where I like the wheel centered. Usually it ends up a 1/2" more forward than stock. Mock up front fenders, stand back and eye ball it. Having your rear where you want it also helps in the end. JMO
I would drop a plumb bob from the front or rear of each side of the differential tubes at the backing plates and make a mark on the floor at each side. Then I'd snap a straight line laterally between the two marks. Then I'd measure forward 115 or 116 (this length doesn't matter, as long as it's the same left to right) inches from that line on each side and make two more marks on the floor, one on each side and snap another straight line between the front marks. Measure between the lines at each side to make certain they are parallel. Then I'd drop a plumb bob down at the front on each side to the line on the floor and hacksaw mark the frame where the plumb bob string touched the frame. You could move forward or backward from your hacksaw marks the same on each side when you position the MII crossmember and know positively that you are parallel with the differential housing. You have no way of knowing if the frame has ever been tweaked at the front, so measuring from some front hole in the frame is worthless. Doing it my way guarantees that the lateral centerlines of the rear and the front are parallel, regardless of the past history of the frame itself.
What happens when all is said and done and you put your fenders on only to find that one or both wheels look "goofy" to far back or to far forward? I have seen many older cars/truck that were never hit be 1 1/2" off from side to side from the factory..........................
I'm not saying put the crossmember in on the saw marks. I'm saying that if you have saw marks that are parallel with the rear diff housing, you can move the crossmember forward or rearward from those marks to get the tires where you want them in the wheelwell and know that the crossmember is in the car parallel with the diff housing. The saw marks are just a reference point to start from so that you put the car together square. It doesn't matter if the saw cuts are 110 inches from the diff or 120 inches from the diff or whatever, just so long as they are the same distance from the diff on each side of the car at the front. It also doesn't matter where the wheelbase figure ends up, as long as the car has the same wheelbase left to right so that it doesn't "dog track" going down the road.
I under stand what your saying friday, I just don't explain myself very well! Doing it your way implies the rear is in square to begin with and most I have seen are not.......... So to be "correct and dead on" you would have to take it to a frame shop (3-4 hun) and have everything squared up first THAN take it home and start cuttin................ Most would not do that and I have never done that on any of the clips I have done.......
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