Originally from September 2001 StreetTrucks Magazine Installing Mustang II IFS in a 1967-1972 F-100 BY: OGNC For more than 20 years, there has been an entire industry driven by the need for better front suspension, steering and brakes for classic cars and trucks. And while there are a lot of different variations of aftermarket independent front suspension to choose from Camaro, Volarie, etc. without a doubt the most popular are the kits based on the Ford Mustang II. Kits to adapt the Mustang II-style independent front suspension can be found to fit everything from 1932 Ford Coupes to 1965 Chevrolet Novas and even the Ford F-150 (up to 1996) and Ranger pickups (up to 1997) that were built with I-beam front suspension. And while Fords Twin I-Beam front suspension was undeniably durable and worked flawlessly in off-road trucks, when it came to street performance, ride quality and even getting the wheel alignment set the Twin I-Beams werent the best choice. When it came time to lower a truck that had the Twin I-Beams up front, you almost needed a degree in engineering to get everything right. We can't count the variations of radius arm relocation modifications and steering setups that weve seen over the years on Rangers and F-150s that have been lowered more than four-inches. Then if you want to run air bags it opens up a completely different can of worms. Thats why when we decided to start working on our 1968 Ford F-100 project truck, the first thing that we wanted to do was replace the factory front suspension with a Mustang II Style front end from Fat Man Fabrications. Brent and the rest of the crew at Fat Man Fab (or maybe we should just refer to them as the Fat Men.) have a complete weld-in front suspension kit that comes with everything that you need to get the front of your F-100 riding, steering and stopping like it should. While they make Mustang II-style front ends for practically everything under the sun, this particular kit is one of the most popular among classic truck enthusiasts. Thats because it doesnt just upgrade the suspension system, it also replaces the drum brakes with modern discs. Since we had already removed the motor and transmission and all of the front sheetmetal from the truck before we got started, it only took one day for the talented crew at Devious Customs to remove the Twin I-Beam setup and replace it with the Fat Man Fabrication Mustang II. Granted, having the truck taken apart prior to the suspension really helped speed up the process. But the easy to understand instructions, the simplicity built into the kit and the fact that the Devious crew does stuff like this all day long, every day of the week really helps. With that said, feel free to follow along as the crew from Devious Customs spends a day changing our F-100 for the better. If you have any questions about any of the parts or procedures on the following pages, or want to know if a Mustang II-style front end is available for your application, feel free to contact either of the companies listed at the end of the story.. The basic kit from Fat Man Fabrications comes with their crossmember and uses stock Mustang II control arms, brake struts, coil springs, spindles and brakes. But since were suckers for cool looking upgrades, we went for the tubular upper and lower control arms (the new lowers are wider and eliminate the need for a brake strut). We also went for the drop spindles, power rack and pinion steering unit, ECI brake upgrade and a set of Devious Customs own air bag mounts (not pictured). It all starts with putting the front of the truck up on jackstands and the removal of the factory front suspension. The I-beams, radius arms, steering box and anything else that isnt going to be used anymore is removed from the front of the truck. As you can see, the pile of scrap parts is pretty serious and it only got bigger as the day wore on. After everything that needed to be unbolted was out of the way, the frame rails were measured to ensure that they were straight and a piece of 1-1/2 inch tubing was welded into place between the frame rails just behind where the core support mounts. This is to keep the frame rails square when the factory front crossmember is cut out. Before any cutting is started, the front axle centerline is marked on the frame. This is to show where the center of the factory front suspension is and will work as a reference for installing the new crossmember. After the centerline is marked in the frame rails, the factory spring cups are cut down to allow Jeff to double check his axle centerline marks. Because Davy likes to measure twice and cut once, he bolted the fender back on the truck and used a wheel off of another truck that is being built at the shop to double check the axle centerline marks. As it turns out, the factory axle centerline put the front wheels too far back in the wheelwell opening. So he put a second mark on the frame ½-inch further forward than the factory centerline to center the front axle in the fenderwells. After all of the axle centerline drama unfolded, they proceeded to use a torch to cut all of the heads off the rivets that hold the factory spring cups to the frame and pushed them through with an air hammer. Then whats left of the spring cups just falls off on the floor. Then the plasma cutter is brought out to cut the crossmember out from between the frame rails. After the crossmember drops out, the gussets that are inside the frame rails have to be cut down so that they dont stick out any further than the top of the frame rail. And the reason that the gussets have to be cut down is because the front sections of the frame rails have to be boxed. Here, they are making the cardboard template that they will use to mark the ¼-inch steel that will become the boxing plates. The shape of the template is transferred onto the ¼-inch steel and the plasma cutter is used to cut out the boxing plates for the frame. Both of the boxing plates are then welded into place inside of the frame rails. Because there is going to be a lot more welding done around the new boxing plates, a 4-inch grinder with a sanding disc is used to clean up all of the welds and provide a smooth surface to mount the new Fat Man Crossmember. The center of the crossmember is then lined up with the new axle centerline that was marked on the frame and each side is tack-welded into place. After it is tack welded into place, the measurements are double and triple checked. After everything checks out, the crossmember is completely welded into place between the frame rails. With the crossmember in place, it is time to setup the upper control arm mount/coil cups (or hats) on the top of the frame rails. The hats have a hole in the center of the coil cup that traditionally serves as the upper shock mount and these holes have to be a certain distance apart according to the instructions. After their position on the frame is determined, the rears of the hats need to be notched to fit down over the frame. This is because there is a certain amount of anti-dive that is built into the front suspension by leaning these hats back a certain amount on the frame. Once the backs of the hats are cut to clear the frame, they are slid into place and welded to the frame rails. With the crossmember and the hats welded into place, Jeff hangs the suspension together to double-check the height of the air bag mounts and because he knows that the frame rails are going to have to be notched for the steering. After the rack and pinion steering unit is bolted into place, it is clear that even at drive height, there is going to be issues with the steering and the frame rails. I guess thats why the kit comes with C-notch sections for the frame and instructions on where to put them. The c-section for the steering is then welded into the frame. Because the front of the F-100 is wider than a stock Mustang II, the Fat Man Fab kit also comes with a rack extender that simply bolts to the rack to push entire tierod assembly out to make the rack wider. As you can see the tierod is removed, the rack extender is simply screwed into place and the tierod is reinstalled its really easy to do. Jeff also welds the gussets for the hats into place as well as the supports for the tubular lower control arms. Since the front suspension is going to be setup to run air bags, the front shocks have to be moved to a position behind the front suspension. Since we told the Fat Man Fab crew we were going to run air bags, they already had the lower shock mounts on the control arms. Here, the position of the upper shock mounts is located and the tabs are welded on. The shocks are then installed on both sides. At this point, the radius arm crossmember is cut out completely. Since there arent radius arms on the truck any longer, there is no need to keep the crossmember so it is trashed. Since the upper shock mount wont ever be used to mount a shock, it is drilled out and a plastic sleeve is inserted into the large hole to protect the airline that will soon be running through it. Fittings to accommodate the ½-inch air line are installed on the Firestone Air Springs and the upper mounts are installed. The airline is plumbed into the air bags and the assembly is installed in the Fat Man Mustang II front suspension to button things up. The final piece of the puzzle is the installation of the new disc/drum master cylinder. We picked one up at the local auto parts store using the application recommended by the instructions that come in the kit. PARTS: FAT MAN FABRICATIONS 8621C Fairview Road, Highway218 Charlotte, NC 28227 (704) 545-0369 www.fatmanfab.com Installation: DEVIOUS CUSTOMS 2314 S. Vineyard Ave. Unit J Ontario, CA 91761 (909) 947-1800 www.deviouscustoms.com
OGNC, Thanks for the tech! Here's a shot of my 72, I took a cheaper aproach for the drop. I used the front end from a 81 lincoln, It was free! The Lincoln, Grand Marquis, and LTD frontends are a pretty easy install and here in Mich. the frames tend to rot out to the rear of the splice line so donors can be had cheap. Oldtin
I wondered who owned that 72...nice truck!..I think I remember seeing that pic on a F-100 website... I like the LTD/Marquis clips too......they work really well on F-100's... I've owned 3 Ford trucks with them...........and have nothing but swell things to say
Radshit, Thats the same pic from the ford enth. site all my others died with my old computer. I also did the lincoln clip on the red 68 on my site, I used a 77 on it though, before I found out how well the 80 up clips worked. The earlier lincoln clips work better for 57-64 ford trucks because the steering gear is behind the wheel centerline so you can keep the same column angle. Oldtin
Yea, I used a '70 LTD clip on a 62 F-100...The steering box lined up perfect with the 77 T-bird tilt column I used....all bolt in....even the brake lines from the equalizer valve lined up with the T-bird master cylinder I bolted on to the firewall...... Plus not to mention, I used factory Ford engine mounts for a 460, 390, 351C, 302....hehe...I ended up playing musical engines with that truck....
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