I ordered the Comp High Energy 268 yesterday along with the other two kits that includes the rest of the valvegear matched to the cam (magnum roller rockers). Has anyone had any experience with this cam? It's going in my 81 350 with Carter 625 carb, Edelbrock Performer EPS intake, Davis HEI, Dynomax headers and stock TH350 with stock 2.82 rear end. I'm running stock compression of 8.2 :sleep: and was looking more for a torque boost than HP. Any ideas how much rear wheel hp/torque the cam and valvetrain alone is worth? Comp tech rep said the cam would make plenty of vacuum so I took his word on that.

 

I'm kind of in the same boat you are. I am looking at increasing the power of my 79, L82 and am not sure what cam to install. I was looking in the Jeg's parts catalog and they show many different brands of cams but they don't use the same way of discribing them. I was looking at the same cam you were and I don't want to go too radical with the engine but I want to give a good boost of power. I'm not even sure what a 79, L82 came with compaired with what is available. It would be nice if someone would help us both out. :confused: Who did you talk to when you made your mind up as to which cam to order?

Thanks; Mike

 

Mike;

I called Comp Cams directly and spoke to a tech rep. Told him what I had and where I wanted to end up and he was very helpful. I got the cam and both kits from the tech rep so I know everything is matched. Be prepared to be on hold for awhile though - but it's their nickel with the 800 #.

I'm not going to get it installed for a couple of weeks but I'll post my view of it then.

 

See my reply in your thread in the C3 forum. :cheers:

 

Jon;

Thanks for the info I'll give Comp Cams a call and talk to a rep. about my engine and see what they have to tell me :yesnod: .

Mike

 

Your L-82 is an emission controlled version of the '69 L-46 with a lower compression ratio. The biggest power drag is the single converter, so if you don't have to be emission tested, backdate the exhaust system to full dual without a converter. That will be good for more power from off idle to about 50 HP at the peak. The OEM 962 cam is tough to beat in terms of overall torque bandwidth in a 350.

Duke

 

Do you have an automatic or manual trans? If you have an auto and are running stock convertor without higher stall speed theres gonna be draw backs with the 268. Especially with a 2.82 rear. With 8:1 compression yur gonna loose cylinder pressure at lower rpms with that cam. With stock stall and automatic trans its gonna be sluggish out of the hole untill about 3000rpm. I wouldnt go higher than XE262 with those gears and stock stall auto trans. Im runnin 2004r trans which has 2.74 first gear plus 2200rpm stall and 3.90 rear. I had the 268 and downgraded to the 262. I like the 262 much better. It idles better in gear. Good enough to be left in gear at a stoplight. The 268 was rougher at idle in gear and forced me to bump it into neutral till the light turned green. The 268 did have slightly better top end. It was not, however, worth the sacrifice of smoother idle and better bottom end in my opinion. Not even with my higher stall and lower rear gears.

 

Hi John;

Were you running the 268 with 10.1 CR? That cam is not made for anything above 9.1.

Comp advertises the 268 for use with a stock converter. I'm going to try and get the CR up a couple of tenths with a steel gasket. Heads are down the road for when I get a 383 short block built (probably next winters project).

 

Jon, actually I was running the XE268 first. for reasons still unknown it wiped a lobe. The cam was great for my application with higher stall and low rear gears and the lower first gear of the 2004R trans. I was happy with it although it did have noticably less TQ of the line then the stock cam. When the lobe wiped I decided to downgrade to the XE262. Much happier with the 262. The cam you chose is in the H catagory I believe. H268? Anyhow, regaurdless of what the manufacturer says im making my statement from my expierence between my two cams. I believe that manufacturers commonly understate the negitive effects on bottom end with respect to thier high perfromance cams. It is still my opinion that you will loose off line TQ with the H268. And with a TH350 with stock convertor and 2.82 gears, you may wind up being disappointed that the "overall" gain may be little to none with yur current convertor and gears. Im not saying the cam wont work for you, but if you plan on keeping those gears and stock stall speed, you would do better with a smaller cam. Thats my guess from my expierence.

 

I was kinda short on fast cash, so after I paid almost 3k to have my L-48 become a b&b 383, I retained the stock exhaust for a year. I also had the stock torque converter, and rear-end gear of 3.36:1. I used a new set of assembled world sportsman II heads, with a new set of roller-tip stamped rockers, and used my performer manifold, with a holley 650. Instantly, I had a HUGE IMPROVEMENT over the wimpo motor I had before. As I added the larger carb, new 3.70 rear, RPM Air-gap, Holley 750, Hooker Headers, Pro-Magnum roller rockers, etc. etc., I added more and more power.
I've seen this cam in a hot rod or chevy high perfomance article a couple of years ago, where the motor was a 355 with TFS or AFR heads, and made 455 hp on 87 octane gas! Of course, no water pump, exhaust, pwr steering, a/c, alternator, smog pump, etc. , but still a worthy number.

When I consulted CC help line, the dude told me that the XE268 is the most radical cam you can use, that still makes enough vacuum to power the accesories, plus works with the stock torque converter. Those qualities, the fact that this cam is used often in proven recipe motors in magazines, and the power gains that future upgrades bring, sold me on it.

I think that this cam works very well in a 350, but I might do a little better with the 280XE in my 383. But I probably wouldn't be able to pass my emission tests with a cam like that, so I'm stickin' with the 268XE.

 

Sorry, I coulda sworn the title of this thread was X-treme energy 268...
Not High Energy 268.

Same manufacturer, but I think the HE is a single pattern, while the XE is a dual pattern. Plus there might be some differances between the opening ramps.

Jvette73 is right about the XE262 vs. the XE268. The XE262 has more torque.
I saw a huge differance when I installed the new 3.70 rear, along with the 2,100 stall converter.
I forgot to mention that when I spoke to the tech line, the dude asked me what my performance goals were, what parts I currently have, and what parts I was planning to purchase. The XE268 worked for me with the stock tq converter, and 3.36 rear, but the cam really craves something more like a 3.70 to 4.11 with about a 2,100 to 3,000 stall speed.

Recently, a car mag did a dual pattern vs. single pattern comparo article, while testing a set of "home ported" heads.
They used the XE268 dual pattern on two tests, one with the unported heads, and the other with porting. Then they got the single pattern HE268 (which has lower overall lift compared to the XE268), and tested that with each of the ported or unported heads.
I don't have the numbers available here at work, but there was a significant differance in power between the single and dual pattern cams. The single pattern HE268 made more HP and TQ than the XE268 dual pattern.
They did say that the heads they used flowed great on the exhaust side, and that the dual pattern's longer duration, and higher lift on the exhaust, might've actually hurt the motor's ability to make power.

My advice for the future is to eventually get yerself a new/rebulit rear end... it will give you more bang for the buck (in my eyes) in terms of neck snapping acceleration vs all kinds of motor tweaking.