Which cam to use?
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Which cam to use?
Ok, i have a a 350 with pro heads(200cc intake) with a performer RPM intake, holley 650 DP, MSD Pro-billit ignition, headers, & 2.5" duals. I have a hydraulic cam with a .454" lift now and it just doesnt seem to pull like a champ. Im putting some 4.11 in the rear anyday now which will help, but i was just wandering if i need to go bigger on the cam?.......maybe upwards of a .500" lift.
Any suggestions would be appreciated.
[Modified by OBL1V1ON, 10:19 PM 5/11/2003]
Any suggestions would be appreciated.
[Modified by OBL1V1ON, 10:19 PM 5/11/2003]
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Re: Which cam to use? (stalker)
Specifications:
* Advertised duration: 272 intake/272 exhaust
* Duration at .050 in. cam lift: 216 intake/216 exhaust
* Gross valve lift: .454 in. intake/.454 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 2,000 to 5,000
* 8.75 to 10: 1 compression ratio recommended
Hope that helps...
[Modified by OBL1V1ON, 9:58 PM 5/11/2003]
* Advertised duration: 272 intake/272 exhaust
* Duration at .050 in. cam lift: 216 intake/216 exhaust
* Gross valve lift: .454 in. intake/.454 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 2,000 to 5,000
* 8.75 to 10: 1 compression ratio recommended
Hope that helps...
[Modified by OBL1V1ON, 9:58 PM 5/11/2003]
Drifting
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From: Northampton Ma
Re: Which cam to use? (OBL1V1ON)
It depends on your intended use. The Comp Cams 274XE, the Magnum 270H, or the Magnum 280H would all be good choices, but with the XE series of cams, you have to run about 9.5:1 or less compression, but they can have detonation problems with anything higher. If you have 9.5:1 or more, than than 270H or 280H would be the best. From the combo you listed, I'd personally go with the 280H. I'll run them all on Desktop Dyno and let you know what it comes up with. I'd also call Comp Cams and get their recomendation :cheers:
[Modified by Ryan77, 10:44 AM 5/12/2003]
[Modified by Ryan77, 10:44 AM 5/12/2003]
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Re: Which cam to use? (Ryan77)
as far as compression goes, the heads i have have a 64cc chamber the pistons are flat top with 4 little indentions along the diameter and a raised ring around the outside....so i dont really know my compression...
Drifting
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From: Northampton Ma
Re: Which cam to use? (OBL1V1ON)
With the 64cc chambers, I'm sure you have atleast 9.5:1 compression unless you have really low compresion pistons. I ran the combos on Desktop Dyno, and here's what I got:
274XE-- 376hp@5500 and 390ft/lbs@4500
270H-- 360hp@5500 and 397ft/lbs@4000
280H-- 372hp@5500 and 388ft/lbs@4500
These are with 9.5:1 compression.
With 10:1 they look like this:
270H-- 370hp@5500 and 405ft/lbs@4000
280H-- 380hp@5500 and 395ft/lbs@4500
Judging by this I'd probably go for the 270H, unless you prefer high rpm driving.
PS- when you said pro 200cc heads I figured you meant the Dart 200's
274XE-- 376hp@5500 and 390ft/lbs@4500
270H-- 360hp@5500 and 397ft/lbs@4000
280H-- 372hp@5500 and 388ft/lbs@4500
These are with 9.5:1 compression.
With 10:1 they look like this:
270H-- 370hp@5500 and 405ft/lbs@4000
280H-- 380hp@5500 and 395ft/lbs@4500
Judging by this I'd probably go for the 270H, unless you prefer high rpm driving.
PS- when you said pro 200cc heads I figured you meant the Dart 200's
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Re: Which cam to use? (Ryan77)
Wow thnx for the info. Thats interesting. :thumbs:
By pro heads i meant Pro-action heads. they supposedly have better flow rates than dart, and are supposed to be the best on the market right now. Thats why i got them.
is there anychance you could use your program to see how much hp im making with the cam i have now? :D
By pro heads i meant Pro-action heads. they supposedly have better flow rates than dart, and are supposed to be the best on the market right now. Thats why i got them.
is there anychance you could use your program to see how much hp im making with the cam i have now? :D
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From: ewa beach HI
Re: Which cam to use? (OBL1V1ON)
The pistons you describe sound like the factory low compression pieces. These pistons combined with a .040" head gasket and a 64cc chamber would give you around 8.9/1 compression. Not too bad, but that would explain your less than powerful feeling. Also, those heads are little big for a 350 with that low of compression. You can get the compression up by changing to a .015" headgasket such as a felpro pt#1094. That would give you about 9.4/1. It's really hard to suggest a cam without knowing what type of trans you have and if you have an auto; what's the stall speed of the converter? Running your present combo on the desktop dyno; 333hp@5000rpm and 383ftlbs@3500rpm. It has been my experience that this progam is typically "optimistic". Let me know what trans/converter you have and we can run a few different combo's across the "dyno". Once you get those 4.11s and a cam to go with them, you'll be smokin' 'em all the time!! ;)
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Thread Starter
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Re: Which cam to use? (stalker)
As far as transmition goes i have a th350. I dont even know what the stall is but i will probably put a new(higher) one in as soon as i get a manual valve body and start working on the transmition. We used felpro gaskets so i might have the .015" which would be nice.
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From: Severna Park Md
Re: Which cam to use? (OBL1V1ON)
If yur gonna go with a bigger cam than what you have definatly run at least a 2500rpm stall vertor. Check out the Comp Cams XE268. Dur@.050 224/230 lift .477/480 with 1.52 rocker ratio. Then if you want more you can jump to 1.6 rocker ratio. If you go to big with the cam to begin with, you cant back down without another cam swap.
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From: ewa beach HI
Re: Which cam to use? (OBL1V1ON)
The easiest way to tell weather you put in the .015" headgasket is the color of the gasket. The thin ones are steel shim with a black coating on them. Most of the other FelPro head gaskets are blue and around .040". If your head gaskets are blue I suggest you change them when you do the cam swap, I know it's just a half a point but the difference is noticeable. On the converter I would go with something in the 2400-2800 range. That will allow you to run a cam that has somewhere around 230degrees duration @ .050. I've had good luck with COMP CAMS 280H in combinations like yours. A combo like this typically comes in at around 350hp at around 5500 rpm with MAX torque coming in at around 3500 rpm. I hope this helps...have fun
Drifting
Joined: Jul 2001
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Re: Which cam to use? (OBL1V1ON)
Geeze with 4 series gears you can run about any cam within reason but I would take a serious look at the Crower Solid Lifter Flat Tappet cam ,,the part number ends with 0321. It is one sweet little street cam
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Re: Which cam to use? (mountainmotor)
well guys thnx for all the help i really appreciate it. But, i think i have decided to stick with the cam i have and go with some higher ratio roller rockers. I was thinking 1.65. I think with this ratio rockers plus having a 4.11s in the rear my car will pull a little harder. Any comments or suggestions? BTW does anyone know what ratio rocker arms came on 79 vettes from the factory?
