2001 Ford Mustang Cobra - Shift Delight

Horse Sense: NMRA Pure Street engine builders have really pushed the technology of the venerable pushrod Ford 5.0 V-8. Even with factory hydraulic lifters, they've been able to use lightweight valvetrain components and modern camshaft designs to allow these little 310-inch motors to spin well past 8,000 rpm.

The world of heads-up Mustang drag racing is one of compromise, dedication, and sacrifice. The sanctioning-body rule makers control the combinations and-with the stroke of a pen-your hard work, testing, and research can go down the drain. This can be extremely tough on the lower classes, which by their nature are the most monitored and limited classes offered. Take the NMRA's wildly popular Pure Street class for example. It's limited (for pushrod combinations) to a small hydraulic-roller cam (0.500-inch lift max), 311 cubic inches, street-type cylinder heads and intake manifolds, and base weights (3,100 pounds) that deter gutting a car's interior, but racers in P/S have still run in the 10.30-10.50 range with regularity. You don't really appreciate those numbers unless you've tried to run mid-10s with your street car using a supercharger, a huge camshaft, and race-ported cylinder heads, only to come up a second short of your intended goal. Nope, P/S racers are truly a special breed-a group of Mustang racers who can make a 311-inch street Mustang get up and beg.

Maximizing what you have and what the rule makers allow you to get away with has always been a fascinating concept for Denny Hioureas of Orland Park, Illinois. A friend introduced Denny to P/S, and from then on he's worked steadily to improve his program. "My friend Bob Smith used to race Pure Street back when Tommy Payn was the man to beat. Bob passed away, and I bought the car from his wife. That's how I got my start. It wasn't the best car-not compared with what the cars are today-but it was a good, solid car that I had some history with.

"The Cobra [pictured here] was purchased in February 2001 from Total Performance [Clinton Township, Michigan] as a body-in-white. After a few weeks, we began to assemble a rolling chassis. Once the car could be rolled out of the garage, it went to the chassis shop for a 12-point 'cage and frame connectors. I picked up the car, and then it sat in the corner of my garage for over two years. During that time, I campaigned Bob's '91 hatchback, but I struggled to stay competitive in P/S. This class leaves no room for error-the hatch's chassis wasn't up to the part, and the drivetrain just wasn't as fast as the Big Dogs. I finally parked the '91 hatchback and took the cover off the body-in-white. We began by installing all new front-suspension components, the fuel system, interior, and glass. We tried hard to have the car ready for the '04 season, but that did not happen. My brothers, George and Sam, and I work together at our dad's repair shop where we all work six days a week. All our spare time and effort were put into this car after work and on the weekends. We finally got it done in time for the '05 NMRA Joliet event."

The brothers' thrash session focused on transferring everything from the '91 to the new car while updating and modernizing the suspension of the '01 Cobra to maximize what power can be made from a P/S engine combination. The car responded with a best of an 11.13-second e.t. at 122 mph with a 1.42-second short time-not a record setter, but a much better start than he had with the old car.

Along the way, Denny picked up quite a few P/S tricks he was willing to share with our readers. One of the most interesting aspects of this car is it makes more than 400 hp with a stock computer processor without an additional tuning or piggyback computer system. Denny says P/S racers on a budget should install a computer processor from a '95 Mustang GT five-speed car. He says the rev limiter with this computer was set at 7,000 rpm versus 6,250 rpm for the more traditional EEC IV processor. That's a neat trick for any street 'Stang looking to pick up some valuable rpm without bumping the rev limiter.

Denny has also been fortunate to enjoy the engine-building talents of Ed Curtis and his Flow Tech Induction team. When speaking with Ed, you realize that, like most naturally aspirated classes in any form of heads-up racing, P/S is all about rpm. As a general rule, for every 500 rpm you can raise the operational range of an engine, you'll be rewarded with a tenth off your e.t.

"Denny's got what I would describe as an entry-level P/S combination," Ed told us. "That's not to say that he can't win with it, but it's not a $30,000 race engine like shops are selling these guys. We've got him set up to shift the car at 7,500 rpm. Once we get the clutch setup right and the chassis working-I like to see high 1.30s out of P/S car-then we can raise the rpm limit to more than 8,000 rpm. When Darrin [Hendricks] made his run in the "Twin" car [to an NMRA championship], he was leaving the line at 8,800 rpm! We can do that with my combination of parts-we don't bottom-out lifters; we don't use exotic, expensive stuff; there's just some oil-system tricks and lightweight valvetrain parts."

In case you're wondering, Ed's entry-level package is in the $16,000 range. So that gives you an idea of what kind of jack a P/S racer has in his car before he goes testing, blows up a few clutches, bends a few pushrods, and snaps a few other parts. Ed is also adamant about the importance of low-lift flow-rate numbers of P/S heads. At 0.500-inch lift (the max in the class, remember), Denny's Trick Flow Twisted Wedges flow 296-298 cfm and 200 cfm on the exhaust. (The variation is from intake runners.) Ed also sets up these guys with a camshaft that is in the 0.485-0.495-inch-lift range, or well under the maximum allowed so that his customers won't have a problem during a tech inspection. Remember, Pure Street is heavily policed, and Thom Bates, NMRA's technical director, just loves to yank these engines down to the crank-no kidding-to make sure everyone is playing by the rules.

The cool thing about the combination Denny employs in P/S is that its roots lie squarely in the street 5.0 arena. Great combinations that maximize efficiency and flow velocity of the passages of air coming into the engine can create a devilishly fast street 5.0. It's not uncommon to find a healthy street 5.0 car with a little hydraulic-roller and head/cam package like this that will run mid-11s on drag radials while knocking down close to 30 mpg. Good stuff.

One of the aspects of Pure Street that's often lost by fans is how much fun these guys and gals are having in just the pure act of driving their cars. Denny told us he never raced a stick car before. He drove them on the street for years, but never raced them. As most of you know, Tremec is the sponsor for NMRA's Pure Street, and you can't help but immediately acknowledge their enthusiasm when you see a Tremec representative getting a front-row seat to watch this class run. Getting that clutch just right, pulling the first two gears with the front end of the car in the air-that's what it's all about. Denny never thought that having so much fun would land him in the pages of a car magazine.

"I never thought someone like me would make it into 5.0 Mustang & Super Fords magazine. The car you took pictures of before mine was Mark VanMeter's [see "Pegging the 'Meter," Mar. '06, p. 116]. I'm just an average guy, and this means the world to me! Thank you."

In the future, Denny's car is getting a new Ed Curtis short-block, and he'll finally address his computer issues. A new EPEC, tuned by Clayton Racing, will be installed to fine-tune the combination as well as limit the factory rev limiter. And, for Denny, that's just one more step up the ladder in one tough class. "I don't race all the NMRA events," he says. "It's just tough with work and life. I can't eat, sleep, and live this lifestyle. Once the car has Ed's new short-block in it, I need to go testing. I would like the car to be competitive. I don't want to run 11.00s and go home first thing Sunday morning. With the upgrades I'm planning, it should go 10.80s with a good tune."

Denny's engine for 2005 is what Ed Curtis of Flow Tech Induction calls his "entry-level" P/S effort. While nothing is entry-level in heads-up racing, Ed has had good success with this parts combination and his fine-tuning. The stock block uses all lightweight internals (Eagle crank, Probe Ultra Light rods, and Diamond pistons) to make one mean little 310-inch terror. It taps out at 406 hp on a Mustang dyno. The power comes from the Flow Tech Induction top-end package consisting of Trick Flow Twisted Wedge heads, a custom, hydraulic-roller camshaft of less than 0.500-inch lift (per the NMRA rule book), and a Holley intake that has also been the recipient of some port work. An ignition system made up of largely MSD components, Kooks 1 7/8-inch long-tube headers, and a stock computer working a set of 30-lb/hr injectors make up the supporting equipment. Making more from less is what NMRA Pure Street racers do better than anyone.