The main thing we are really trying to find is the rpm, Rick Anderson explains. I think that is going to be the future, so we want to push that limit as far as we can. The learning process right now is the lobe design itselfnot the duration, not the lift, not the lobe separation. Its the lobe design itself that can make as much horsepower as you can with the most aggressive lobe that you can, but not float the lifters. As you can see by checking out the cam specs with the On the Dyno sidebar, cams with similar duration numbers produced disparate results, simply based on the shape of the cam lobe.
If you get hung up on reading cam cards and looking at peak horsepower numbers, this graph should blow your mind. The PS.017 and PS.040 cams have similar specs, but there is an 18hp difference in peak horsepower. More importantly, the PS.040 carries power out past 6,500 rpm, where the PS.017 gives up around 6,500. The sweet spot Rick was trying to find was making good horsepower while maximizing the rpm potential of the engine, which ultimately creates more power in a more usable package. As you can see with the more aggressive duration of the PS.030 cam, it made more peak power, but floats the lifters around 5,800. According to Rick, a cam that signs off this early is practically useless due to the 4.30-4.56 gearing required to get a Pure Street car down the track most efficiently.
The cams tested in this story were purely for development purposes, but obviously the PS.040 cam pointed Rick in the right direction. He plans to offer three Pure Street cams with entirely new lobe designs based on what he learned. Once those cams are proven, they will sell for $269. An AFM cam/spring package will sell for around $375, depending on the cylinder head.
Ricks 5.0 coupe has seen innumerable blower combinations and dyno pulls, but this season he converted it to Pure Street trim so he could develop these cams and race something low-maintenance. His top priority is assisting with Brian Meyers Renegade racer (Four-Speed Steed, Dec. 2000, p. 44). The combination used to develop the Pure Street cams was built around a D.S.S. Super Pro Bullet short-block. Its topped by Stage III AFM/JDC Trick Flow Twisted Wedge heads, a Vortech Shootout Series upper intake, and a Holley SysteMAX II lower intake with a Stage II port. The engine breathes through a Pro-M 80mm mass air, an AFM Power Pipe, and a 75mm throttle body. An Aeromotive pump and 30 lb/hr injectors feed the fire, while a complete Bassani exhaust handles the smoke.
Rick has several test cars running developmental camshafts. This carbureted Pure Streeter, run by Eric Rogers and Jeremy Embry, runs consistent 11.60s with one of Ricks cams and one of his brother Rons Marx carburetors. Rick says the carbureted and fuel-injected cars are really close these days thanks largely to the modern EFI intake manifolds and PMS tuning. As such, camming the two combinations is really no different. 5.0
Over the course of the 2000 season, the National Mustang Racers Association's Pure Street class has really come into its own. Certainly Tom Payn has emerged as its first star, but with 20 racers vying for 16 qualifying spots at the Byron, Illinois, race it's easy to see there are plenty of speed freaks interested in naturally aspirated racing.
Of those 20 cars, the top 10 qualified in the 11s. When you consider intake, cam, and head limits on this class (check out the complete rules at www.nmraracing.com/ rules/pure.html), this is simply amazing. "When I read the rules, I thought they did an excellent job," Rick Anderson of Anderson Ford Motorsport says. "It's flat-top pistons, and it's not aggressively milled heads, 58cc combustion chambers. That's something a real guy can put together in his garage. Then it's the long-runner intakes. That's a lot of cars that we've done in the past.
It's still a car that a kid can drive on the street if he wishes and go to the track. That's why we got excited about it, and we wanted to see how far we can push that envelope."
By pushing the envelope, Rick is talking about the new line of cams he is developing for the class. As with his popular cams for the power-adder Renegade classes, these new Pure Street cams are designed to deliver max performance within the rules. When he asked us if we'd like a glimpse at the development process, we jumped at the chance. What our sneak peek tells us is the Pure Street cars are going to run even harder next season.
Pure Street was designed for street-oriented 11- and 12-second small-block, naturally aspirated Fox-chassis Fords, including '96-present 4.6 Mustangs. Limits include a maximum displacement of 310 ci and a maximum tire size of 26.5x10.5 inches as measured. Its 16-car qualified fields run on a pro tree (0.400) NHRA sportsmen ladder.