What you will read and see here will be information received from Duane Carling, the owner of CTM Engineering. We offer this webpage because of our interest in unusual suspension. Please feel free to contact Mr. Carling if you are interested in his independent rear suspension for early Mustangs:
"See the lower control arm on the rear suspension? That car was built by Ford in 1964 with full independent rear suspension, 4 wheel discs, and rear knock off wheels. That setup was supposed to be on the Shelby GT-350". Those were the words of Wally Peat, who was showing me through his personal files of 60's racing memorabilia.
With the help of several people from the 1960's Ford racing teams, including Carroll Shelby, I have spent the several years tracking down a bolt in independent rear suspension (IRS) that Ford made for their first Mustangs. Three or four were built in Dearborn and tested at Shelby's place in California. Some early ones were run under Falcons, since the Mustang was still under development using the Falcon platform.
Lee Iacocca thought the Corvair Monza was the target for his new "sporty car," so would need IRS, a 4 speed, disc brakes, and true knock off alloy wheels. Little did Lee know, the Mustang would tap an undiscovered market, which had nothing to do with Corvairs or Monzas. The new Mustang was straight forward (compared to the Monza) looked sporty, make the person driving it look sporty, and cost about $2000. With a V-8 it offered tire burning excitement to the macho crowd, and with luxury options it could be a mini T-bird for the gentleman sportster. With a six and automatic it was also the perfect secretary's car. There was even and ad campaign called "Six and the single girl".
The IRS and disc brakes cost slightly more than the solid axle, and when the Mustang was introduced it sold well enough without it, so the corporate bean counters killed it. Their only concern was making enough Mustangs to satisfy the tremendous demand. Iacocca hired Shelby to build the GT to keep up the sporty image of the Mustang.
Several years ago I was doing a story on Wally Peat, race car mechanic and fabricator extraordinaire. Wally worked for Shelby building the King Cobras, which were Ford powered, tube framed, single seat race cars based on the English Cooper. Wally's Cobras tore up the West Coast pro racing circuit in the early 60's, leaving Ferraris and other high dollar Europeans to wonder what hit them. Wally was showing me through his files, and came across a tricked out '64 Falcon with IRS and 4 wheel discs. Wally said, "We were developing it on a Falcon because the Mustang was still a year away."
I vaguely recalled reading aout the IRS Mustang in the 60's car magazines, and the intriguing memory led me to Lew Spencer at Shelby's office in California. Lew remembered a name "Klaus Arning, probably retired by now." who was the suspension designer at Ford. After several false leads in Dear born, I finally found a name in the Detroit area that sounded like it could be right and called it. Klaus turned out to be a very personable guy, remembered the Shelby crew, and was interested in seeing if we could revive the IRS project. The Palm Spring Historic Races put on a Shelby roast in conjunction with their races about then (I can't believe that was 1990!) so we arranged a meeting with Wally, Klaus, several of the old crew, and of course Carrol. Lee Holman Jr., son of the stock car builder was also there, which proved to be a lucky coincidence later.
Tracking down a little known engineering project done by a team of guys 30 years ago proved to be much harder than I though it would be, even with their leader helping me.
Some of the original documentation still existed. Klaus called one day and said, "I went to the archives. I showed them my credentials. They gave me the microfilms. I'll send you the prints." When the rolls of blue prints arrived about a week later, I felt like Indiana Jones about to unroll the treasure map to the ancient vaults.
Unfortunately, the drawings were incomplete, and the parts list was written in a Ford Experimental Dept. nomenclature, no longer used, that is nothing like 1960's production numbers. It was piece of the puzzle though, and started me on the trail to find out what all those numbers and letters meant.
"Nope, never heard of numbers like that. They aren't in my computer, and aren't even in my old parts books. What kind of car are they off of?". If you've ever tried to explain to a parts guy what part you want, but don't know the exact year and model of the car it came on, you probably know the frustration of trying to deal with a clerk raised on computers and quick reference screens. Supposed Ford parts experts were baffled by the hand witten lists.
Finally one day I was in the small Utah town of Logan, where my wife's uncle runs a Ford dealership started by his father many years ago. With a couple of hours to kill, I walked into the old parts department with my now well worn list, and asked the young guy behind the counter if he could translate it.
"Come back into the back, and let's look at some old books." said the parts man. "Ford used to send out a hard cover volume every year cross referencing experimental, engineering and casting numbers with production numbers. We have them all from the early 1900's up to 1967, when they stopped doing it".
Even though he couldn't have been born when the Mustang was introduced, the parts guy had access to and knew more about the numbers I'd been carrying around with me for 2 years than all the old timers who'd been telling me it couldn't be done. In a room behind the regular parts shelves, into what was obviously a treasure trove of almost unknown books, was the reference system used in the days the IRS was developed, but now long forgotten even by those who once used it.
Crossing experimental numbers with production numbers from 1960 and '64, I knew I'd found the Rosetta Stone of the IRS! A list of bushings, tie rod ends, nuts, bolts, and special production Ford hardware began to emerge from those old pages. None of it was in stock at the dealership(of course), but armed with my now readable list I drove the 100 miles back home so excited I could hardly stay on the road. My long suffering wife had to listen, again, to how great this was going to be when the IRS was finally back on the road, after being buried by Ford 30 years ago.
When I rolled out the drawings, I could see Klaus and the Experimental Dept. had use bushings from the front suspension of 60's Fords and Falcons as noise and vibration isolators to mount the leading and trailing arms of the IRS to the frame of a '64 1/2 Mustang. Using a Jaguar center section with Dana 44 guts, a fabricated lower control arm, and using the half shaft to complete the parallelogram of a fully independent suspension was the key to this design.! Klaus used the same basic concept for the 427 Cobra rear suspension which he designed in 1965.
I now had most of the production Ford and Jag pieces. What I needed were the special fabricated parts, such as the hub carriers (uprights in race car talk) that had all the geometry built in, to make a Mustang handle like a Cobra.
I called Lee Holman a week or so later, to tell him of my good fortune. He said he knew of some strange parts, supposedly left over from the IRS project, which had been purchased from Holman & Moody years ago by a collector of rare Fords(who prefers to remain anonymous). Lee said he'd call him to see if he still had them. Weeks went by, and I forgot about it until the collector called me from the Salt Lake airport. He was just passing through, and wondered if we could have dinner. He turned out to be a great guy, and a few weeks later UPS delivered 3 greasy packages, with about half the missing parts I need, including a left and right hub carrier. I now had the critical parts needed to make Klaus's geometry work and move the way it's supposed to. The parts were a loan, if I'd find the missing pieces, and return the originals with all the parts necessary to make a complete assembly.
Assembling what I had, I could see that tie rod ends and other production suspension pieces let things swivel, pivot and move to make a true 4 bar, fully independent rear suspension worthy of any race car. And, it BOLTED in where the solid axle mounted on the production car. Nothing had to reinvented. Everything fit. The finest traditions of American hot rodding had been applied to Detroit's newest `1964 sporty car.
Most of the guys that helped me on this project will be getting together at the SEMA show in Las Vegas in a few weeks. I'll have an IRS equipped Mustang for them to drive again, 30 years after they developed it, and it disappeared.
The above, was written in 1994
The prices listed below, are from
1998, they have changed by now.
The Basic Kit: $3,000.00 + Tax
Includes all items unique to the T-5 I.R.S., such as coil-over shocks, hub carriers, control arms and new cross members.
The Deluxe Kit: $4,500.00 + Tax
Includes CTM basic kit, plus Ford brake discs, calipers, bushings, Jaguar bearings, assembled hubs.
The Premium Kit: $5,000.00 + Tax
Includes CTM basic and deluxe kits, plus all the nuts, bolts and misc. hardware to make this a true bolt-in operation.