Hydraulic Roller Cam - Wake Up 'Stick

Roller-Cam Upgrade Gives a Veteran Warrior Loads More Fight

John Nelson Feb 26, 2008 0 Comment(s)
0803chp_11_z Camshaft 2/12

The vast majority of gearheads fall into two categories when it comes to choosing a camshaft: those who go too big, low-end torque and driveability be damned; and those who go too small, ensuring good street-going manners while leaving the performance potential of their powerplants unfulfilled.

The cold, hard truth is that guys who get it just right, picking a 'stick realistically matched to their engine combo and intended use, are in the minority. And that's unfortunate. We're not saying it's easy to pick the right cam, but if you're brutally honest about your goals and intentions--and willing to accept the counsel of experts--there's no reason not to have an engine that delivers exactly the powerband you're looking for.

By all accounts, Pete Cervantes created a stout little 383 stroker for his '69 Nova, seen in our June '07 "Horsepower Rules" compendium of 10 proven street/strip machines. A larger 'stick was discussed with the engine builder at the time of engine assembly, but the decision was made to go a conservative route to ensure good street-going manners. A Comp Cams XE268H hydraulic flat-tappet cam (PN 12-242-2) was slid into place, sporting 224/230 degrees duration at 0.050, 0.477/0.480 inch lift (punched up to 0.510/0.512 inch with 1.6:1 rocker arms), and a 110-degree LSA. The Nova threw down respectably with 353 hp at 5,800 rpm and 375 lb-ft of torque at 3,900. It's had a good, torquey powerband and responded well to the squeeze--on a 125 shot, the '69 ripped off an 11.84 at 117 mph, which is nothing to turn your nose up at.

On the other hand, Cervantes couldn't help but wonder what could have been had he gone with a more aggressive cam of the roller variety. We decided to take up the challenge and got on the horn to one of our favorite cam experts, Comp's Billy Godbold. We did what you should do when picking a cam: We sent Godbold the engine and vehicle specs and Cervantes spelled out exactly what he was looking for: a broad, flat, street-friendly powerband that revved a bit higher than before--and would also enhance the nitrous experience. "In other words," Godbold said, "he wants it all." Well, who doesn't?

Godbold considered our specs and performance goals and came back with a curveball: one of Comp's new Xtreme Fuel Injection cams, a 280XFI HR13. This 'stick runs 230/236 degrees at 0.050, along with 0.576/0.570 inch lift, and has a 113-degree LSA. Our response, of course, was, "You know the thing has a carb on it, right?" We briefly debated the issue but got past the hangup once Godbold explained the method to his madness. We really wanted three things: more power, a wide powerband, and good performance on nitrous. "The lobes we use in the XFI cams are the best design we have, period," Godbold declared. "All the engine cares about is the cfm the head is flowing, so the sooner we can get into higher lift the better the head looks." So not only did we increase lift, but we were also able to get into that lift at a quicker velocity--thanks to both the nature of a roller cam in general and the XFI lobes in particular. In this way, we took maximum advantage of the good-flowing ported and polished heads. The combination of the other two goals led us to the other critical factor: "No doubt that 113 LSA is producing a very flat torque curve and it works good with nitrous," Godbold continued. "We'd have gone with a tighter LSA without the nitrous."




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