Michael Johnson
Associate Editor, 5.0 Mustangs & Super Fords
April 20, 2007
Andy Juhl's '98 Cobra convertible could be confused with any other Mustang with big and littles and a hood. But under the Kaenan Cobra R hood lies a supercharged Four-Valve easily capable of obliterating the Mickey Thompson E/T Street Radials living out back. Anyone thinking the Takash Racecraft 'cage is just for looks is mistaken. Eagle-eyed 'Stangbangers will know that the Weld Racing Pro Stars aren't XP models, which necessitate a swap to SN-95 GT brakes.

Horse Sense: Andy Juhl says this Cobra didn't save him any money compared to taking his former GT convertible to the next step. "It would've cost me the same amount to redo the GT, as well as saving me a lot of time and aggravation."

Many Mustang owners have come to a fork in the road on their journey toward a certain performance point, where they realize that to go any further will be a lot of work. The majority of us begin with a heads, cam, and intake package. After that comes the supercharger. At that point, the T5 is crunching and grinding its guts out, so it has to be replaced. Besides, if we really want to go fast, we'd need a built short-block, and then the car needs a 'cage. Soon comes the realization that it's better to buy a Mustang that already has all that stuff and the hard work is done.

That's what Deltona, Florida's Andy Juhl had in mind when he reached that juncture with his '94 GT convertible. When Andy bought the car, it was stock. Under his performance eye, the droptop featured AFR heads, a Holley SysteMAX II intake, an Anderson Ford Motorsport B-21 camshaft, and a Vortech S-Trim pullied for 12 pounds of boost. The GT was good for more than 470 hp and ran 11.90s at 124 mph with factory A/C and a good stereo. But he wanted more. He thought of adding a Dart block with forged internals with a bigger blower or a turbo. "This would mean restarting and spending a lot of money-again," Andy says.

"I figured I would sell the GT and find a car that already had what I wanted-or close to it-and save some time and money." A twist came when Andy decided he wanted to stay with an SN-95 body, but this time he wanted Four-Valve 4.6 power underhood. "I knew the 32-Valve Cobras were making really good power with only a power adder, and the short-blocks could handle it with the addition of rods and pistons." So he looked for a '96-'98 Cobra, and his first night online turned up this car.

The ad said, "'98 Cobra convertible with a ProCharger F-1R blower, built forged motor with less than 2,000 miles on it, new transmission, F.A.S.T., and rollcage." It was the exact color Andy wanted at a price he couldn't pass up, so he bought it. "The only problem with the car I saw was the transmission wasn't going in and out of lockup," he says. He also wanted to get it on a dyno to see if it was tuned right, so he took the Cobra to Jake Lamotta at Lamotta Performance-Jake did the work on Andy's former GT convertible. "The first thing he asked me was if it had billet oil-pump gears because there were problems with the stock gears falling apart on higher horsepower Cobras," Andy says.

With that question, the Cobra's honeymoon abruptly ended. Andy didn't know if the engine featured billet oil-pump gears, so Jake took a look. "That's when it all began," Andy says.

Since we had to drive Andy's car to the photo shoot location down the street from Lamotta's Performance in Longwood, Florida, we tested the car's Cobra Monaco seats and felt the B&M Hammer shifter. The Takash Racecraft 10-point 'cage is omnipresent, but it's also necessary so Andy won't get booted from the track after one nine-second run. We couldn't hear much of the stock stereo over the exhaust due to the lack of rear speakers, although we couldn't care less. The guy giving us the thumbs-up on the way back to Lamotta's signaled that he couldn't care less about the stereo, either.

When Jake pulled apart the front of the engine to get a closer look at the oil-pump gears, he discovered the balancer rubbing against the timing-chain cover. Boss 330 Racing's Al Papitto happened to be at Jake's that day, and he surveyed the situation as well. "He went to the car and put his hand on the crankshaft's snout." Andy says, "The crank moved in and out and clunked around." For those keeping score at home, when your engine's crankshaft moves in and out and clunks around, that's bad. "Let's just say the engine had more than 2,000 miles on it," Andy says. It could have had only 2,000 miles on it, Andy, but those miles were spent on the rev limiter.

Nevertheless, the engine came out and Al took it to Boss 330 Racing for a rebuild. Once Humpty Dumpty was put back together, there were problems with the cams, which had come in the engine when Andy bought the car. They outfitted the heads with a set of Crower Stage 2 camshafts, which made power, but the numbers weren't where Andy wanted them. The dyno curve was erratic, going from 500 to 475 to 535 to 480 hp, and so on.

Jake told Andy this was common on power-adder Four-Valves, so he offered two choices. The first involved rewiring the ignition and F.A.S.T. system. The second was to add a distributor to the Four-Valve, which Jake assured would fix the erratic horsepower numbers. Andy chose the second option, and he was happy with the results. "The engine ran better than ever and made more power."

During this time, Andy also saw fit to upgrade the suspension and rearend. He had Takash Racecraft convert the 6-point 'cage into a 10-point system. "I knew the car would easily be in the 10s," he says, "but with all the money and time I had in it, I was hoping for 9s."

Remember the aforementioned transmission woes? Well, it also needed to be rebuilt. Andy didn't have it done until the car was back together, but the transmission troubles pushed him to the point where he didn't even want to drive the Cobra. He took a step back and had Performance Automatic go through the transmission. Andy hasn't returned to the track since running 9.80s at 139 mph, but he says, "even if it's not faster at the track, it drives a lot better on the street since the rebuild." Andy, in his role as Captain Obvious, says, "I guess the transmission wasn't new, either."

The moral of his story is this: you never know what you're getting when you buy something used. "You could get lucky or you could be like me," Andy says. "The whole car has been redone, including the engine, the transmission, the suspension, the rollcage, the brakes, the wiring, the distributor, and a bunch of odds and ends." At least Andy can take solace knowing the car is now done, and done right.

Al Papitto at Boss 330 Racing built the 283ci Four-Valve with a Cobra crank, Manley rods, and CP forged pistons with Mahle piston rings. Al also treated the B-heads to a valve job, stainless steel valves, and Crower Stage 2 camshafts to match the company's valve springs. The Cobra intake received porting, shortened runners, and an Accufab throttle body. All-important billet oil-pump gears make sure everything is well lubricated. The focus on lubrication is due to a couple of things. First, the Four-Valve engine likes to rev. Second, the ProCharger F-1R just fore of the passenger-side cam cover is capable of forcing 23 pounds of boost down the Four-Valve's throat. The stealth exterior gives way to a ferocious symphony of supercharged power when this thing is running. The sound belies the 9.80s Andy's Cobra blasts at Orlando Speedworld Dragway.

5.0 Tech Specs
ENGINE AND DRIVETRAINELECTRONICS
BlockEngine Management
Cobra aluminumF.A.S.T.
DisplacementIgnition
283ciMSD distributor, 7AL-3 ignition
Rotating Assemblywith an HVC II coil, 8.5mm spark
Stock crankshaft, ATI balancer,plug wires, AGSF 22C spark plugs
Manley H-beam connectingGauges
rods, CP forged pistons, MahleAuto Meter {{{Phantom}}} tach, boost
Performance piston rings,and fuel pressure, Innovate
billet oil-pump gearsMotorsports wideband
Cylinder Heads 
Stock Four-Valve B-heads,SUSPENSION AND CHASSIS
valve job, stainless steelFront Suspension
valves, Crower valvespringsK-member
CamshaftsAnthony Jones Engineering tubular
Crower Stage 2Control Arms
Intake ManifoldAJE tubular
'98 Cobra ported, shortenedCaster/Camber Plates
runnersSteeda Autosports
Throttle BodySprings
Accufab single-blade ovalQA1 175 in-lb coilover
Power AdderStruts
ProCharger F1-R and three-coreLakewood Industries {{{90}}}/10
intercooler, Cog-pulley withBrakes
40-tooth blower pulley, 23-lbsSN-95 {{{GT}}}
boostWheels
Fuel SystemWeld Racing Pro Star 15x3.5-in
Walbro 2025 fuel pump,Tires
Aeromotive fuel pressure regu-Mickey Thompson 26x7.5-in
lator, 72-lb/hr injectors, braidedRear Suspension
stainless steel -10 sump to pump,Springs
-8 pump to engine, -6 return fuelEibach Pro-Kit lowering springs
lines, billet fuel railsShocks
ExhaustCompetition Engineering three-
MAC ceramic-coated long-way adjustable
tube headers, custom 3-inControl Arms
X-shape crossover, MagnaflowSteeda Autosports aluminum lowers,
mufflersadjustable uppers, antiroll bar
TransmissionBrakes
Performance Automatic SuperSN-95 GT disc
Comp AOD-E with 2,800-stallWheels
converter,manual valve bodyWeld Racing Pro Star 15x10-in
and transbrake, B&{{{M}}} HammerTires
shifterMickey Thompson E/T Street
Rearenddrag radial 325/50
8.8, Spool, Moser 31-spline axles,Chassis Siffening
4.30 gearsTakash Racecraft 10-point
 chrome-moly 'cage