So what's the main difference between these 2 different designs of cams. The XE is only a little more in $.

 

The older (20 sonme yrs old now) Magnum designs are single pattern. The XE designs are dual pattern with much more agressive ramps, but designed in such a way as to set the valves down as gently as possible to prevent valve float. A typical result of faster, cheaper, more MFLOPS processing power over the last couple of decades. Basically you get more effective "area under the curve" valve opening, i.e. flow, without the idle quality and gas mileage and low-RPM driveability problems that the older cams used to cause.

Spend the $$$, you'll make it all back in like 2 tankfuls of gas. It's a total no-brainer.

 

The Extreme Energy series use a Magnum Exhaust lobe.
Combined with a Extreme (more intense) intake lobe.

Supposed to have more open area under the lift curve
resulting in more air flow with less seat duration.

These "fast action" profiles require more spring pressure to control the valvetrain because of this.

THere is a definate limit as to how fast you can open a valve for a certain diameter lifter. Hyd profiles are also further limited
buy the need for quiet opertation.

Comp is pushing the limits closer to the edge, with these designs. Wether wear and tear are comprimized is another story.

People seem to like them.

Crane has had a simular series on the market for Years.
"HMV" for Hydraulic Maximum Velocity" and "Hi- Intensity"
Are their marketing names. Now combined under "Power Max"
and "Energizer"

Although they are measured differently to establish the advertized seat duration, they are real simular in design.
Comp measures at .006" and Crane measures at .004" or .0045"
This gives slightly larger advertized numbers for the same .050"
lift cam. But they are actually very simular if measured using a standard reference.

Most "Marine and industrial design" lobes don't try to push the limits quite as much for durability reasons. They have to last a lot longer. So need to use lighter valve springs.

All these new design highly A-semetric, hi velosity, high lift lobe designs seem to be a nice improvement over the old "Muscle car era" cams, but again need close attention to the valvetrain setup to be sucessfull.

 

Those extreme energy cams are definitely worlds better than any other cam I've ever tried in my firebird or camaro. With a extreme 262 cam in my girlfriends 305 L03 camaro it ran 98mph in the 1/4 with just intake, headers and 3.42 gears (no posi either) I attest the great mph to the cam since the heads were 100% stock. I have the 284 extreme energy cam in my firebird and it hangs door to door with my buddies solid roller cammed aluminum headed 85 trans am, and my car has cast iron heads, so I'd say go with one of the extreme cams and don't look back.

 

Oh I wasn't considering trying to save $10, I just wanted to know why if the XE is so much better why people still go with the Magnums.

 

People get good results with both design series....

The XE series has the *potential* for a broader torque curve
and better vaccuum and throttle response, and maybe even some more hp than a more conservative design.

The only actual experience I have with them is, a friend has
the XE284H cam in his 383 Edelbrock RPM head Camaro and it does work well.

Low 12's

 

Well, I'm hoping that with teh 268XE, Stealth intake I will be at low 14s.

Then, do you guys think that it's possible with those and my current setup, but with ported heads and a 2800 stall TC I could be at low 13s?

 

Yes that is quite possible. Your stock Goodwrench motor has quite low compression. though. This will hold you back.You could cure this with a head swap. say some nice ported 58/61 cc heads.

You would want to aim for real near 10.0:1 compression.

 

I see what you mean, but I plan in a year or 2 to put a centrifugal SC on it. And then I would have to lower the compression if I raised it.

 

Put on a real set of high flow high performance heads
like AFR's or BRODIX with 10:1 cr along with your other planned mods before you plunk down $4/5000 for a SC.

http://www.airflowresearch.com/
Build one of their combinations (see dyno tests)
Then tell me you need a SC LOL

You can still SC nicely with 10:1 cr , just have to Intercool or Water Alcohol Inject, to avoid detonation like the big boys do.

SuperCharger!!! I thought you said "Money was tight"???