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Discussion Starter #1
Just wondering if any of you guys have tried Comp Cams Xtreme energy 274H cam in a 302. I'm running one now and wondering if the cam may be too 'big' resulting in a loss of power or is it my rear gears causing the problem. Specs are 230/236 duration at .050 and 520/523 lift, 110 lsa. I was running the old Crane Blazer 288-2H with 218/230 dur @.050 with 488/498 lift, 114 lsa and the car seemed more responsive with the 'old' cam. Rest of engine specs are 10/1 compression, 4v heads, dual plane intake, 650 double pumper, headers, and 2.5 inch exhaust. 4 speed and the rear gears are 3.00,... So is the cam too much or is it just the bonehead move of not yet having taller gears in the rear?
So..any ideas?? Thanks.
 

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im not the best here with cams but AYYY .. yes that sounds like a big cam for a 302.... it can be done but im sure that the 3.00 gears are hurting you a bit. i mean, hell i have a 351W ( stock cam ) and i hate the 3.00s. ( exc on the freeway :) ) even with the 4 speed it sounds like a mismatch of stuff there. now oyu have an excuse to get new gears eh? he he
 

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Well I've gotta agree with sixt9coug on this that cam sounds pretty big for a 302 but with some lower gears in the rear say 3.50 or so,that should help to liven it up and get it up into the rpm range it requires for max torq and horsepower. I'm sure some other on here will give you a much better answer than mine but for now GEARS a definite.
 

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Yeah the 274 is going to be soft on the bottom, so taller gears are in oder. I had the xe256 with a stock converter and it had grunt, but it is considerably less duration. I wouldnt expect that cam to come alive until 2400.
 

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The Crane Blazer cam is one of my favorites for a small engine / heavy car. I ran one for 15 years in my daily driver '67 XR-7 with 289 / 4 speed. It provides a healthy low end torque boost, just what you need in a street driven car.

The Comp Cam you mention has tighter lobe centers and more duration at .050" causing loss of low end power and response in a small displacement motor.
 

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That cam is slightly bigger than the one I'm running in wvcat. Mine is 235/520/108 and I'm running a 3:89 gear ratio with a 351w/AOD 10.5 comp & dart(world)sr. heads. My car starts turning on around 3000-3200 rpm and pulls like a bear to 6500. I still have a soggy low end with a 351 so I'm sure your 302 is worse. I am also running rhoads lifters to try and gain some idle quality but that is a hole new debate.
John
wvcat
 

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cam

Are the heads stock 4 barrel heads? The comp cam is better suited for a higher RPM powerband than your old crane. higher gears may help, but unless the rest of the motor is set up to spin well above 6000 (intake ,exhaust,heads) you will only hurt your driveability with higher gears. I run a 448/472 lift cam with less duration than the comp cam and I have 3.70 gears in my cougar with a mildly modified 351 and C6. It screams off idle through 5500 then falls off. But it is well mannered around town. If I went with a bigger cam I would have to upgrade the heads & intake or I would hurt overall performance. I would recommend going back to the crane cam, or doing some mods to the rest of the engine/driveline to catch up with the cam.
Paul G.
69 XR7 Convertible
 

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Discussion Starter #8
The heads are the stock J code heads redone and machined to accept the dual spring assembly with the damper. I have comp cam roller tip rocker in it. Here's the deal..I'm not going to be driving around town screaming at 6000 rpm and i have noticed that the comp cam does not come alive till about 3000 or so. Hence the question as to whether cam or gears? I'm also thinking maybe crane cam's blue racer with 222/234 @.050 and 498/527 lift 114 lsa. Seems to be right between the two cams but I'm not sure how that would work out...I know taller gears are in order no matter what. Should I just go and stuff the 20 year old crane blazer back in there? thanks.

P.S. Wv Cat, I had a funny feeling that was your car on E-bay!
 

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That Crane Blazer is a good cam. Unless you marked which lifter went to where, you will have to buy a new set. Installing used lifters where they did not originally come from will cause rapid cam failure and other engine damage.

If you are set on another new cam look for one with around 218 @ .050 and LSA of 112 or more.

A set of 3.25 gears would allow freeway driving and get back some performance with the Comp Cam you currently run. That ratio is common in Mavericks and Comets from 1970 - 77 with 240 six power. Those cars had 28 spline 8 inch rear axles so the center section transplants directly into a 67 - 68 small block Cougar. They went to a five lug axle in 1972 so even the axles work on the later ones. Junkyards sell such parts really cheap.
 

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Discussion Starter #10
Oooohhh, I'll have to price that at the local yards. Only problem is that a lot of the old stuff is gone out of the yards here in So. Fl. Could just pull out the Summit catalog and put down $$$, ouch.
I did mark the lifters by the way.
 

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I was just comparing cams, and I decided on the CC XE268H for my 351W. On DeskTop Dyno, the 274 just moved my power up 500rpms, without any actual HP gain.

That cam didn't make peak until 6500 on my sims, where the 268H made peak ~6000. You also lose low end by adding so much duration. I think that cam is a 3500-6500 cam.

So whatever you gotta do to keep your car in that range, is what you gotta do to get power out of that cam.

PS: Stock heads are neutering your engine above 5000rpm. So you're probably only making 1500rpm of usable power with that cam and those heads. Something to think about.
 

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Discussion Starter #12
I,m definitely changing the cam. There is no doubt that the duration & lsa of the comp cam is making for a power band that is not where I want it. The good part of it is that because of that cam I now am set up with dual springs, machined heads and roller tip rockers. I called Crane and they recommended the cam I was looking at. Power Max 222/234 @.050 and 498/527 lift 114 Lsa. Anything above that makes for more head work, or different heads and operating in an rpm range that does not make for nice family drives! Definitely will be going to taller gears, 3.25 or 3.55.

Thanks guys for the imput and confirming what I suspected.
 
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