[bowtieorbust]

Hello again, Got a ? about the XE268H camshaft #12-242-12 i purchaced last week from summit, for my 350 sbc. Reason being i had the High Energy 268H for the motor untill my brother had a cam go flat in his sbc, so i gave the cam to him because he was strapped for cash. So i went and i purchased the XE268H (#12-242-2) for my 350 sbc, wich i felt was a little more agressive than the 268H, and would work with my combo a little better. My combo is a 350 sbc, KB .030 flat tops .010 in the hole, S/R torquer heads, .028 GMPerformance gaskets, Edelbrock EPS @ 600 cfm, the tranny is a saginaw 3speed, with 3.40 gears. Well a week after i purchased the other cam, my brother tells me i can have the 268H compcam back, because he got him self another motor and didnt need the cam. So now i have two cams, the XE268H and the H268 wich was replaced by comp a few weeks ago because i dropped one on the floor and it broke in half, (wich was nice of them) Anyhow my lifters and spring will work with either cam, and would like some opinions on what to do, should i use the XE268 cam or take it back to summit and use the 268H cam. (Please Advise)

 

[NXS]

if you have a truck go with the XE and send me the H

:thumbup:

 

[bowtieorbust]

Why what are you gonna put it in?

 

[macx]

Check out Comp Cams website

Look in their dyno results sections,
they dyno the XE268 on a typical
warm street 350.

That SE cam compared to the other will
give you a little higher torque curve
and a tad bit more power on the top,
'but likely be a bit weaker in the low and lower mid range. The non-Xe cam will give you a little bit broader curve without quite as high a peak, and might be a little more street friendly unless your other components are fairly hi perf oriented, like a Perf RPM or single plane intake and some pretty good sized heads.

Also, check the cams out in this Dynamic Compression calculator - the XE cam I know has the intake closing a bit later
which adds to it's higher rpm profile but in turn detracts a little from low and lower mid range because with the intake closing later it doesn't trap quite as much compression - that's why it's important to match the cam to the rest of your setup, esp. head/intake flow capability and check for dynamic compression. I'm sure you can get the valve events off of Comp's site to plug in.

http://www.smokemup.com/auto_math/index.php

Another way of saying would be this:
If you've got heads like AFR's or hi perf Chevy aluminum heads and a Perf RPM or single plane intake AND you have pretty good static compression (small chamber heads and flat tops, like 9.4 or higher) go with the XE (assuming it's not in a heavy vehicle with gears higher than 3:50's, and if it has like a 2500 stall or better if auto). If you have like vortec heads and a Perf RPM or regular Performer and your static compression is like low 9's or lower, go with the other cam, esp. if it's in a little heavier vehicle and/or has gears like above 3:50's and if auto doesn't have much over a stock stall.

Having said all that, double check with comp cams help for their advice.

 

[firestone]

It sounds like you are going to use the old lifters with the new cam. That is not a good idea. As the lifters wear, they get a pattern that matches whatever lobe they are riding on. If you use them on a different lobe, or a new cam, the lifter and cam will will not have a matched surface, and you will get premature wear. If you use a new cam, you should get new lifters also, unless you have a roller, then it doens't matter.

Adam

 

[bowtieorbust]

ThanX(firestone) for the heads up on the wear pattern, but in anyevent both cam are still new and had never been broken-in. But i am thinkin about takeing the XE268 back to summit for a refund when i get thru (Akron,OH) with in the next week or so. I took the oppertunity to put both cams side by side to see how much difference the lobe profiles were, and it didnt seem to me that i would be looseing much with the smaller cam, so ill stick with the High Energy 268 for my truck.imp:

 

[firestone]

Sounds good.

Adam