Our replacement cam of choice was an XFi 280 HR13, which Comp's Billy Godbold calls "the best lobe profile we've done." As for the stick it replaced, the venerable Xe 268H, Godbold says, "it's about as good as flat-tappets get. We replaced our best flat-tappet cam with our best roller cam." What's so good about the new 'stick? Among other things, the intake and exhaust lobes are tailormae for their tasks. Crudely speaking, an intake lobe gets the valve open, lets as much charge in as possible, and shuts. "typically, the exhaust has a smaller closing ramp," Godbold tells us. "there's still flow when it's closing, so we try to smooth it. it's helping to pull in the next intake charge, so we don't want to slam that signal off." the cam is also optimized to work with 1.6:1 rockers and beehive valvesprings. "they work at a high frequency," our guru continues, "and save a tremendous amount ofweight." it works for us.
| BASELINE/MOTOR |
| Timing 38 degrees |
| Jets 75/82; | 32 high-speed |
| | air bleeds |
| Max torque | 375 lb-ft @ 3,900 rpm |
| Max power | 353 hp @ 5,800 rpm |
| Avg. torque | 349 lb-ft |
| Avg. power | 313 hp |
| BASELINE/125 N20 SHOT |
| Timing 38 degrees |
| Jets 75/82; | 32 high-speed |
| | air bleeds |
| Max torque | 547 lb-ft @ 4,000 rpm |
| Max power | 436 hp @ 4,400 rpm |
| Avg. torque | 455 lb-ft |
| Avg. power | 419 hp |
| XFI280 CAM-MOTOR |
| Timing 36 degrees |
| Jets 77/86; | 36 high-speed |
| | air bleeds |
| Max torque | 386 lb-ft @ 4,000 rpm |
| Max power | 395 hp @ 6,000 rpm |
| Avg. torque | 374 lb-ft |
| Avg. power | 337 hp |
| XFI280 CAM/125 N20 SHOT |
| Timing 36 degrees |
| Jets 77/86; | 38 high-speed |
| | air bleeds |
| Max torque | 580 lb-ft @ 4,100 rpm |
| Max power | 474 hp @ 5,900 rpm |
| Avg. torque | 482 lb-ft |
| Avg. power | 457 hp |