March 9, 2007
John Stamper's clean, '90 LX notchback resembles so many other street-going 'Stangs out there. But instead of being a 12-second bolt-on car, this one packs an estimated 700-plus-horsepower surprise under the hood and predicted 9-second elapsed times. Once the blower passes 15 psi and the engine rips past 5,000 rpm, all hell breaks loose.

John Stamper has the right idea about cars. Not concerned with class legislation, he's been content to construct the 5.0 Mustang he wants to build: simple, powerful, and respected. In many ways, the car tells us more about the man who built it than he would ever tell you about himself. In the end, John's goal was simple-build a 5.0 Mustang that's a lot of fun to drive.

With that mature view of what a performance car is all about, you might guess John is experienced about life, and you'd be right. The now 62-year-young is a retired sergeant major from the U.S. Army who was a physician's assistant helping to defend our country until his retirement in 1987. He's always been into hot street cars-his first was a '55 Fairlane with the Thunderbird 312 V-8 option. He followed that up with a '69 Torino that packed the Ford 428 Super Cobra Jet, Ram Air, and a C6 transmission.

After leaving the Army, John turned his focus to the 5.0 Mustang, which at that time was starting to take over the streets of America. Looking for the next big thing in Ford muscle, the 5.0 Mustang was the obvious choice. John bought his notchback and began modifying it with the disciplined planning and execution befitting his military background. In 1995, John opened his own performance shop, Super Chargers Plus [(317) 440-2314] in Indianapolis, realizing that many people could benefit from his experience and skills.

Starting with the exterior of his own car, John didn't waste his money on looks. Nope-this is a down-to-business sort of car for an all-business owner. The Cervini's hood is a great mod, as it dumps some of the front weight and adds style. Other than the lightweight Weld rims, everything is as Detroit designed it or "a subtle little lady going down the street," as John describes the look.

Inside the '90 notch, you'll find stock seating with Auto Meter gauges and a custom switch panel in place of the radio controls. Where a passenger seat once took up residence, John had his brother fab up a trick reservoir out of diamond-plate aluminum to feed ice-cold water to the Vortech Power Cooler. The shifter is attached to a Dynamic C4 automatic with a 3,800-stall that still keeps street driving a reality. The 8.8-inch rear holds 3.55 gears.

But it's no subtle lady when the throttle is cranked. John put together the motor in 1998, and through the years he's bolted several good pieces on the 306. We captured it on film in the summer of 2004. Featuring a Vortech T-Trim, a Vortech Power Cooler, Trick Flow Twisted Wedge heads, and little else, the motor was kicking out more than 600 hp before John shut it down due to lack of fuel during a chassis-dyno test session. Then he popped in some 50-pounders that replaced the overwhelmed 36-lb/hr injectors and added a second Vortech T-Rex fuel pump. To be honest, he's probably still on the dangerous side when the thing hits 26-plus-pounds of boost, but John quickly admits the current fuel system isn't his last.

He chose a proven performer with an F303 Ford camshaft, which was designed to work with supercharged combinations just like John's. Sure, there are dozens of custom blower-specific camshafts to choose from now, but John isn't into giving away his street manners for the sake of some horsepower. We have to say, though, you could probably find another 100 hp in this combo if you started testing camshafts.

"In 1998, it was one of the better cams," John tells us regarding the F cam. "I just built this motor for fun. It had to be street friendly. The F303 doesn't have a ton of lobe, and you can make it idle nicely. I'll tell you, it has a ton of top-end power."

John's suspension is also a study in efficiency and bang-for-the-buck. Koni adjustable struts and shocks make up the bulk of the mods. He replaced the upper and lower control arms with pieces from South Side Machine and Metco, and the front sway bar is long gone. Also helping weight transfer is a set of Moroso Trick springs that John describes as difficult to install but tremendous at lifting the front of the car while squatting the rear.

The performance of John's 5.0 Mustang is mind-numbing on the street, yet the actual numbers have yet to be quantified on a dragstrip. It's a lightweight coupe at around 3,100 pounds with more than 700 hp at the tires. Once the fuel system and tune have been corrected, we're confident it won't have a problem joining the nine-second club sometime soon.

If you doubt that estimate, maybe you should head over to John's shop and check out the car in person. He had this to say about how his Mustang fits into his business plan: "More than 98 percent of my business is installing blowers on stock, street-driven cars. My customers always want to know how much horsepower they make and how fast they'll go. And, the best way to show them what X amount of horsepower feels like is to take them for a ride in my car. Along with the blower kit, they get a ride in the car. I tell them their car isn't going to run like this, but it does give them an idea of what they're in for. You know, when I get on this car, it's just wild. For most guys, it scares the heck out of them."

So-you get a blower install and a ride in this nasty notchback? Where do I sign up, Mr. Stamper?

Horse Sense: The 8-psi Vortech supercharger kit and the Vortech aftercooler sell for around $2,400 and $1,400 respectively. Put that on top of a solid motor with good heads, then add the appropriate fuel system, and you'll be well on your way to making more than 700 hp at the wheels.

The stance of John's street stormer is classic old-school 5.0. Koni adjustable struts and shocks work with Moroso Trick front and rear springs to help plant the Mustang at launch. The front sway bar has been pulled, and Southside lower control arms and double-adjustable Metco uppers work with a Performance Automotive antiroll bar in the back. John installed custom subframe connectors and the 10-point chrome-moly 'cage. The 2.5-inch Cervini's fiberglass cowl hood is the only external mod other than the Weld rims and M/T skinnies and slicks.

When last dyno tested, John's homebuilt motor (circa 1998) laid down 614 rwhp at only 5,000 rpm before the whole deal went lean. Since then, the fuel system was upgraded, and John will be taking his car to Paul's Automotive Engineering in Cincinnati for a fresh reflash of the stock computer. The 306 magic-maker is based on a stock block, Eagle H-beam rods, an Eagle crank, and 8.5:1 Probe pistons. Looking for a street-friendly, fun engine combination, John chose to stay with the F303 camshaft from FRPP. The heads are Trick Flow Twisted Wedge castings that wear 2.02/1.60 valves and were ported by Indy Cylinder Head. An Extrude Honed Vortech/Saleen intake manifold takes more than 26 psi of boost from the Vortech T-Trim.

ENGINE AND DRIVETRAINIgnition
BlockMSD, Taylor Pro Race plug wires, Autolite
Stock (0.030-in overbore)plugs
Displacement 
306 ciSUSPENSION AND CHASSIS
Cylinder HeadsFront Suspension
Trick Flow Twisted Wedge ported by Indy K-member
Cylinder HeadStock
CamshaftA-arms
FRPP F303Stock
Intake ManifoldSprings
Extrude Honed Vortech SaleenMoroso
Throttle BodyStruts
FRPP 65mmKoni
Power AdderWheels
Vortech T-TrimWeld Drag Lite
ExhaustTires
MAC 151/48-in short-tube headers, MAC {{{M}}}/T
211/42-in H-pipe, Flowmaster mufflersBrakes
Fuel SystemStock
Twin T-Rex pumps, 11/42-in feed line, REAR SUSPENSION
31/48-in return line, Vortech fuel rails, Springs
Aeromotive fuel-pressure regulator, Moroso
50-lb/hr injectorsShocks
TranmissionKoni
Dynamic C4 Mitey Mite, Dynamic 3,800Control Arms
stall converterMetco double-adjustable upper, South Side
RearendMachine lower
8.8-in ford w/3.55 gearsTraction Devices
 Performance Automotive antiroll bar
ELECTRONICSWheels
Engine ManagementWeld Drag Lite
Stock computerTires
IgnitionM/T 28x10.5
MSD 6AL BTM, MSD coil, Taylor 409 wires, Brakes
Autolite spark plugsStock
GaugesChassis Stiffening
Auto Meter tachometer and assorted Superchargers Plus custom 10-point
gauges, custom switch panel in radio-chrome-moly 'cage with subframe
delete plateconnectors