#TBT | Rallying a Mustang with a 6.3-liter engine

Staff
By Staff Writer
Oct 26, 2023 | Ford, Mustang, fox body, Ford Mustang | Posted in Features | From the Feb. 2003 issue | Never miss an article

Photography by Tim Winker unless otherwise credited • Lead by Lorne Trezise

[Editor's Note: This article originally appeared in the February 2003 issue of Grassroots Motorsports.]

You stand alongside a road, waiting as each rally car makes its way through the forest. The rumble of a V8 engine is quite a distinct sound among the usual high-revving four cylinders and whistling turbos that you and your fellow rally spectators are used to hearing. A moment later, the metallic blue Mustang roars into sight, tail swinging through the corners as the driver seesaws the steering wheel to maintain control.

Mike Hurst’s Ford Mustang coupe seems like a dinosaur among the all-wheel-drive, turbocharged sedans that are popular with rallyists today. It has the largest displacement engine, is rear-wheel drive and even features a device called a carburetor.

Meet Mike

Mike Hurst is no stranger to rallying, nor to racing with big V8s. His experience with both goes back more than 20 years. Today, he owns a race prep and fabrication shop located in Indianapolis called Tune Tech Motorsports, and he has built cars for many forms of motorsports. 

He attended his first SCCA PRO Rally back in 1980 at the urging of his Northwood Institute in Michigan roommate, who hailed from Quebec and was familiar with the Criterium Rally from that part of the world. He talked Mike into attending the Northern Lights Rally held out of Houghton Lake, Mich. Hurst had read about rallying, particularly the Press On Regardless and how Gene Henderson’s lumbering Jeep Wagoneer–dubbed Moby Dick–defeated all the supposedly more nimble machines from Europe and Japan.

In 1981, Hurst went to work for Dale Arkins’s PRO Rally effort, maintaining an early front-wheel-drive Oldsmobile Omega. Atkins’s codriver was Bill Broderick, a public relations staffer with NASCAR best known as the “hat man” as he conducted the Victory Circle photos and made sure each sponsor’s hat made it onto the winning team’s heads. Hurst’s job as a rally car mechanic was nearly full time, but the promised “big sponsor” never materialized, and the team folded after a couple of seasons.

During 1983 and 1984, Hurst followed the NASCAR circuit as part of the crew on David Pearson’s Chattanooga Chew Chevy. He was one of four full-time employees, the others being Larry Pearson, Ricky Pearson and Larry McReynolds. There was no specialization in those days, as everyone was just a general mechanic. It gave Hurst a well-rounded background in building cars, and engines, for maximum performance.

Hurst’s first rally car was a Datsun 510, the darling of beginning rallyists two decades back. Mike drove it whenever he could in the early 1980s. After a few years off, he returned to rallying in 1988 with an ex-Niall Leslie Nissan 200SX, followed by a succession of cars including an ’82 Toyota Celica and an ex-Steve Nowicki 1986 200SX.

In 1996, SCCA created the Group 5 class, a new category for what had been Open class two-wheel drive cars that were quickly becoming obsolete due to the dominance of all-wheel drive.

Hurst built a Porsche 911 S specifically to contest the new class. The 911 was a mix of pieces: a 1976 chassis with 1986 bodywork and a 1978 engine.

“The Porsche was a nightmare to run,” said Hurst, “because parts were so expensive. While I tried to get away with used parts whenever I could, new parts for it were ridiculous.”

Hurst continued to run the Porsche during the 1998 season while building a first-generation

Mazda RX-7. The RX-7 became the primary rally car later that season and for 1999, but it still did not quite meet Hurst’s expectations.

“The RX-7 was cheap to build,” said Hurst, “but it was hard to find used parts because most of them had rusted away."

Changes for 2000

Hurst and co-driver Rob Bohn started the 2000 season at Sno*Drift in Michigan with a borrowed Pontiac Sunbird Turbo, preferring front-wheel drive for the anticipated snowy conditions. Later in the season, they rented Kendall Russell’s Dodge Shadow GT for Maine, hoping to collect more points in Group 5.

The Mustang was built in the latter half of 2000 and finished in time for the Black River Stages ClubRally in New York, where Hurst and Bohn won the Group 5 class and placed fourth overall. The only other rally they ran that year was the Lake Superior ProRally, finishing third in Group 5 and 16th overall in the Mustang.

Why a Mustang, ask many who follow rallying? There are so many more nimble cars available from Japan and Europe.

“At the time I built the car, I realized I would be competing primarily on ClubRallies in the Midwest,” answers Hurst. “The rally roads in Michigan and Minnesota are pretty smooth. Same with the roads at Camp Maxey in Texas, which at the time was supposed to be the site for the annual ClubRally National Championships. A new event this year was 100 Acre Wood in Missouri, and roads there are like a pool table. So horsepower is important, especially coming out of corners.

“Plus it’s a crowd favorite,” he continues. “Everyone can tell the distinctive roar of a domestic ground-pounding V8 as it comes thundering through the woods. There are always people at Parc Expose and at service areas who tell me how great it is to see a real American car competing.”

More Than a 5.0

The motive power for Hurst’s Mustang comes from the most basic American technology, a big V8 with a big carburetor. Many of the pieces for the engine, and for the car itself, came from parts left lying around the shop and from salvage yards.

The engine is a 5.8-liter V8 (351 cubic inches) that came from a Ford van; it’s stroked to 386 cubic inches, just under the SCCA maximum of 389 for pushrod engines. The crankshaft increases the stroke to 3.85 inches, and the engine has KB pistons and rods from a 351 truck engine. Compression ratio is 11:1. The CNC-ported Canfield aluminum cylinder heads have 2.05-inch intake valves operated by a high-lift, flat-tappet camshaft ground by Comp Cams.

An 830 CFM Holley carburetor sits atop a high-rise, single-plane Edelbrock Victor Jr. intake manifold. Electrical spark is boosted through an MSD 6ALN ignition, with the rev limiter set at 6500 rpm. The oil cooler, filter adapter and thermostat came from an ’85 Ford police car. The Mustang also has a Griffin aluminum radiator, designed for oval track use. Ford Racing headers direct the exhaust through a pair of 2.5-inch pipes and Flowmaster mufflers.

Although the 5.8-liter block weighs nearly 120 pounds more than the 5.0-liter block it replaces, Hurst says he uses it as a way to get “cheap horsepower.” It puts out an estimated 450 horsepower at the flywheel, about double what a stock 5.0 produces.

That flywheel is a billet steel unit, a castoff from another project car. There is a puck-type clutch disk and the pressure plate diaphragm is rated to survive 3500 lbs./in. of torque.

The transmission is a standard Mustang T5 five-speed manual, with the rest of the driveline featuring the stock Ford 8.8-inch axle with a 4.10:1 final drive and a clutch-type limited slip.

Under-car Mods

Rally roads are quite different from the surfaces in most other forms of motorsport, but Hurst has been able to tune the suspension on his Mustang to meet the challenge.

Up front are Ford Motorsport upper control arms, and KYB AGX struts act upon two sets of springs: 440 lbs./in. coils on the control arms and 200 lbs./in. units around the struts. The front anti-roll bar is from a four-cylinder Mustang. The rear shock absorbers are from dirt circle track technology–AFCO Street Srock shocks–with Monroe horizontal shocks used to locate the rear axle.

Four-wheel disc brakes haul the rally Mustang to a stop, but once again they are a hodgepodge of pieces out of a parts book. The fronts have standard Mustang I 1-inch rotors, but the calipers are from a Lincoln Mark VII. Rear rotors are from a 1988 Thunderbird Turbo, with calipers from the front of a 1988 Chevy Monte Carlo. The brake master cylinder is also a Mark VII part.

The parking brake is hydraulic, using a torpedo-style master cylinder plumbed into the brake line. Next to the shifter is a brake bias adjustment valve, but Hurst prefers to adjust the front-to-rear brake bias by using different compound pads.

While exotic wheels are nothing new to rallying, the Mustang usually rides on stock 15x7-inch aluminum wheels from an LX model. “We can buy them for $20 apiece at swap meets,” Hurst explains.

Scrabbling for grip on gravel are BF Goodrich All-Terrain T/As, size 215/75SR15. Hurst tried Kumho rally tires at the 100 Acre Wood ClubRally, bur felt that they wore more quickly than the BFGs.

Hurst starred with a 5.0-liter 1988 LX notchback chassis, which is a bit lighter than the fastback model. He added a fiberglass hood that was picked up at a swap meet for only $80 because it had a flaw that made it unacceptable for use on a street rod.

The roll cage for the 2900-pound car is made of 1.75-inch tubing, supplemented by square tubing for rigidity. The cage is attached to the chassis in more than 60 places, including four tubes forward, and has extra bars reinforcing the area under the seats.

Both Hurst and co-driver Bohn use aluminum stock car racing sears with Simpson harnesses.

Success!

The Mustang has proven to be a successful rally steed for Hurst and Bohn. They have won Group 5 in the last seven ClubRallies they have entered, and despite a limited schedule finished third nationally in Group 5 points during 2001. The most recent victory came at the 100 Acre Wood, where they won their class while taking the 2001 ClubRally Group 5 national championship.

For the past two years, Hurst has also been part of Ted Lyons’s team on the One Lap of America, competing in a fire-breathing 1989 Ford Thunderbird Cobra SC, which Hurst also built at his Tune Tech shop. They finished second in the Mid-priced Sedan class both times.

“One Lap has a class for economy cars, those with an original sticker price under $15,000,” said Hurst. “I’ve been toying with the idea of running the Mustang in 2003, though I would have to redo the suspension since One Lap is all paved racing courses.”

The Mustang has been in rally service for two years now and Hurst is thinking of changing cars again.

“The new Historic category looks interesting to me,” he said. “Maybe a late-1960s Camaro. Wouldn’t that be something?”

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Comments
irish44j
irish44j UltimaDork
3/27/18 4:41 p.m.

The thought of doing stage rally in aluminum kirkeys..... :O

FIYAPOWA
FIYAPOWA Reader
3/28/18 7:40 a.m.

Anyone have any idea where I can find an old rulebook for the SCCA Clubrally?  On a related note, I WAS going to build a roller 5.0 for my rally Mustang...

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
3/28/18 7:43 a.m.

In reply to FIYAPOWA :

I don't know about finding the old rulebook, but I've had two clubrally cars grandfathered into the current ruleset so I'm somewhat familiar with what the standards used to be and how that translates to the current sanctioning bodies, as are some others here.  What did you want to know?

FIYAPOWA
FIYAPOWA Reader
3/28/18 7:50 a.m.

In reply to ¯\_(ツ)_/¯ :

Nothing specific, but one of my projects is a "historic" SCCA rally car which I am trying to restore back to its former glory (within reason).  That being said, since it's kind of a clean slate with most of the original parts missing, I'm willing to take some liberties.  In this article, the "SCCA limit of 389 cubic inches" stuck out to me, so I'm a little curious what a ragged edge of the rule book build would look like...

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
3/28/18 7:57 a.m.

I believe the displacement adjustment chart hasn't changed much, if at all, so for Group 5 you have a maximum of 5100cc with a multiplier of 0.8 for pushrod engines, so up to 6375cc if you keep it pushrod and N/A.  You could do whatever you want to the internals within that displacement.

TIGMOTORSPORTS
TIGMOTORSPORTS Dork
3/29/18 4:57 a.m.

Great example of a Grassroots build that is well engineered

Rallygorgo
Rallygorgo New Reader
3/31/18 6:58 p.m.
FIYAPOWA said:

Anyone have any idea where I can find an old rulebook for the SCCA Clubrally?  On a related note, I WAS going to build a roller 5.0 for my rally Mustang...

I was digging through one of my toolboxes and found a CD of the 2003 SCCA ClubRally/ProRally/RallyCross rules.  I’m pretty sure I’ll never need them so it’s yours if you like it.  Let me know.

Ratchet
Ratchet New Reader
4/4/18 9:17 p.m.

Interesting article about Mike & his Mustang.  I've gotten to know Mike & Rob at S.T.P.R. here in Pennsylvania. Great rally guys !!

PT_SHO
PT_SHO New Reader
4/5/18 5:22 p.m.

In reply to irish44j :

< The thought of doing stage rally in aluminum kirkeys..... :O   >

Got THAT right.  I had one in my autocross SHO, then transplanted it to my STI, both with coilovers, and long distances were NOT fun.  Bought some extra pillows but that still didn't make it anywhere near "comfortable".

Run_Away
Run_Away GRM+ Memberand HalfDork
4/5/18 5:43 p.m.

Clutch rated to 3500 lb-in?

That's an odd metric.

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