Notice this Crane cam has less advertised duration and the same duration @ .050. This makes the ramps more agressive in opening up quicker which translates into more power.
http://cranecams.com/?show=browsePa...37;20C.I.&partNumber=150062&partType=camshaft
Part Number: 150062 Grind Number: 284 H12
Lift: Intake @Cam 320 @Valve 480 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 320 @Valve 480
Rocker Arm Ratio 1.5
Cam Timing: TAPPET @.004
Lift: Opens Closes ADV Duration
Intake 31 BTDC 73 ABDC 284 °
Exhaust 75 BBDC 29 ATDC 284 °
Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 7 BTDC 41 ABDC 107 228 °
Exhaust 51 BBDC (3) BTDC 117 228 °
Now, click this link
http://www.compcams.com/technical/Catalogs/106-07/26-37_228-229.pdf and scrool down to the second Magnum cam, camshaft part number 20-232-4 and see the duration numbers.
280 advertised, 230 @ .050 with .480 lift
While the lift isn't larger than the Cranes, it's profile is larger, by a tad. 4*'s less advertised duration. This makes this cam a hair quicker in the lift area.
Now here is a Bullet cam. Notice that the advertised duration is also 296 but the duration @ .050 is stout by compare to the one our looking at;
part#; 3049696 239/239 296/296 507/507 106
http://www.bulletcams.com/BulletCatalog.htm
And even more so a difference in this Comp Cams roller cam;
Duration at 050 inch Lift: 242 int./248 exh.
Advertised Intake Duration: 280
Advertised Exhaust Duration: 286
Lift; 0.570 int./0.576 exh. lift
(If this don't wake up your engine..........OK, well, not your stock engine...)
The quicker the rise, the better off you'll be and more power you'll make.
Purchase a cheap cam, you might very well get what you pay for. Nothin.