A Fortunate Choice Of CamsI wasn't looking to fit my Small-Block Showdown 383 with a nitrous-friendly cam-it just worked out that way. Nitrous HP camshaft number 12-419-8 is ground with the numbers I wanted. It's got lots of lift and pretty good duration for a street cam, and as I observed back in Sept. '06, the lobe separation angle of 113 degrees would allow for a decent idle and adequate vacuum My idea was that this cam would give this engine a fighting chance of passing a smog test (at the pipe, of course) if I decided to sneak it into a smog-era car. This isn't really what Comp Cams had in mind.
Nitrous HP cams are designed to work well without nitrous, but also to deliver "incredible gains" when on the squeeze. Comp engineer Billy Godbold was only too happy to elaborate for me. "The Nitrous HP uses the same intake lobe as an Xtreme Energy 288 cam," he began. "This makes it a good midrange cam." The difference is on the exhaust side. "We use a bigger exhaust lobe," he explained. "We also use a 113-degree LSA and a 5-degree advance for earlier exhaust valve opening. This cam works well with nitrous, but also with anything that has a faster burn rate." Higher-compression engines fitted with good heads make good use of a Nitrous HP cam.
The idea, he elaborated, is to reduce pumping losses. The exhaust valve opens early, and for a long duration, meaning less burnt gas needs to be pushed out on the piston's upstroke. "We get more out for free," Godbold summed up. "It does give up some low-end, but it carries better past peak power." We didn't notice any loss of low-end power, but we did notice the aggressive note created by the long exhaust duration. "The power curve is moved up," Godbold told us, "but the sound might be worth it." We'll go along with that.