i am looking to get a little hotter setup in my car. see my signature for the current setup. i plan on changing to an edelbrock vortec performer rpm intake, msd 6a ignition box, and either an edelbrock performer rpm cam or the comp cams XE 274. id like to leave everything else the same....dont want to spend too much money . im looking mainly for performance at the drag strip....im sure both of these will be streetable enough for me. i was thinking the xe274 might be a little better matched with the rest of the car, but the edelbrock still might give me some better times at the track. which cam do guys think i should get? here is some specs on each:

edelbrock performer rpm cam-
* Advertised duration: 308 intake 318 exhaust
* Duration at .050: 234 intake 244 exhaust
* Gross valve lift: 488 intake 510 exhaust
* Lobe separation: 112 degrees
* RPM range: 1,500 to 6,500 RPM
* Designed for optimum torque from low end to the mid range, for daily driven vehicles.

comp cams xtreme energy 274h cam-
* Advertised duration: 274 intake/286 exhaust
* Duration at .050 in. cam lift: 230 intake/236 exhaust
* Gross valve lift: .487 in. intake/.490 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 1,800 to 6,000
* Very strong mid-range torque and throttle response, 2200+ torque converter

 

The RPM cam is a joke. This isn't even a contest, in the real world. There's no way, in any car I can imagine, that it would run better or go faster.

 

why is it so bad?

 

Because it is such an old design. Not that it is "bad" but that technology has come a fair ways since Edelbrock had that cam designed.

Edelbrock is bringing out newer designs, however. I know that they have fresher grinds in the roller cam side of it.

 

I think you would be happier with the X274h. The ramp rates of the RPM cam are very lazy (slow to open, slow to shut). Although they have very similar duration figures at .050" the Comp cam has about 30° less of advertised duration.

Basically, the longer it takes (the larger the difference between advertised and .050" durations) to go from the seat to .050" of tappet lift, the longer it takes the valve to reach peak lift figures. The longer it takes to reach peak lift figures, the shorter amount of time the valve spends in the higher lift ranges. The shorter the amount of time the cam keeps the valve in higher lifts, the more power is "lost."

Basically, the Xtreme Energy cam raises the lifter/opens the valve faster and keeps in opened in the higher lift ranges longer than the RPM cam.