Need cam selection advise...
Thread Starter
Racer
Joined: May 2004
Posts: 288
Likes: 0
From: Tigard OR
Need cam selection advise...
I'm getting ready to put together a 383 to replace the tired 350 in my 69, which has a turbo400 tranny and 3:36 gears.
I want a car with good torque and throttle resonse, I'm more interested in low to mid torque than high end horsepower. I'd like to keep the 3:36 gears and have great throttle response.
Here is what I was thinking of:
383
10.0 - 10.5 to 1 compression
Dual plane intake
180 cc RHS ProAction aluminum heads
650 or 750 CFM Speed Demon ?
1 5/8 long tube headers with 2 1/2 exhaust
Appropiate stall speed converter ?
Hydraulic roller cam
I was thinking of this cam:
Comp Cams Magnum 280HR 08-430-8
224/224 .525/.525 110 LSA
What do you think of this combination and cam choice?
The only parts I have purchased at this time are the intake and heads.
I want a car with good torque and throttle resonse, I'm more interested in low to mid torque than high end horsepower. I'd like to keep the 3:36 gears and have great throttle response.
Here is what I was thinking of:
383
10.0 - 10.5 to 1 compression
Dual plane intake
180 cc RHS ProAction aluminum heads
650 or 750 CFM Speed Demon ?
1 5/8 long tube headers with 2 1/2 exhaust
Appropiate stall speed converter ?
Hydraulic roller cam
I was thinking of this cam:
Comp Cams Magnum 280HR 08-430-8
224/224 .525/.525 110 LSA
What do you think of this combination and cam choice?
The only parts I have purchased at this time are the intake and heads.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
With that cam I would keep the compression around 10 to 1. Those heads don't have a real good I/E ratio and with 1 5/8 headers you might look at a dual pattern cam like this for 10 to 1
http://www.cranecams.com/?show=brows...tType=camshaft
Or this one if your going a little more radical. Can run more compression too.
http://store.summitracing.com/partde...2&autoview=sku
Remember the descriptions are generally based on the manners the cam would have in a 350. A 383 will need more cam to acheve the same manners as a 350.
http://www.cranecams.com/?show=brows...tType=camshaft
Or this one if your going a little more radical. Can run more compression too.
http://store.summitracing.com/partde...2&autoview=sku
Remember the descriptions are generally based on the manners the cam would have in a 350. A 383 will need more cam to acheve the same manners as a 350.
Last edited by 63mako; Mar 3, 2008 at 11:44 PM.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
With a stock torque convertor this is about as big as you would want to go for a street cam: Comp XE series hydraulic roller CS XR264HR-10(specs at this link) http://www.compcams.com/Technical/Se...umber=08-412-8
Le Mans Master
Joined: Dec 2006
Posts: 5,557
Likes: 9
From: Oquirrh Mountains
St. Jude Donor '09
I'm getting ready to put together a 383 to replace the tired 350 in my 69, which has a turbo400 tranny and 3:36 gears.
I want a car with good torque and throttle resonse, I'm more interested in low to mid torque than high end horsepower. I'd like to keep the 3:36 gears and have great throttle response.
Here is what I was thinking of:
383
10.0 - 10.5 to 1 compression
Dual plane intake
180 cc RHS ProAction aluminum heads
650 or 750 CFM Speed Demon ?
1 5/8 long tube headers with 2 1/2 exhaust
Appropiate stall speed converter ?
Hydraulic roller cam
I was thinking of this cam:
Comp Cams Magnum 280HR 08-430-8
224/224 .525/.525 110 LSA
What do you think of this combination and cam choice?
The only parts I have purchased at this time are the intake and heads.
I want a car with good torque and throttle resonse, I'm more interested in low to mid torque than high end horsepower. I'd like to keep the 3:36 gears and have great throttle response.
Here is what I was thinking of:
383
10.0 - 10.5 to 1 compression
Dual plane intake
180 cc RHS ProAction aluminum heads
650 or 750 CFM Speed Demon ?
1 5/8 long tube headers with 2 1/2 exhaust
Appropiate stall speed converter ?
Hydraulic roller cam
I was thinking of this cam:
Comp Cams Magnum 280HR 08-430-8
224/224 .525/.525 110 LSA
What do you think of this combination and cam choice?
The only parts I have purchased at this time are the intake and heads.
http://www.compcams.com/technical/Dy...68H-10_001.asp
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,501
From: Little Rock AR
I think you will do well with cams close to the size you have selected but you might want to spread the lobe centers a bit for better street manners. The 383 can certainly run well with 110 degree lobes for higher peak power but if HP was your first priority you could (should) even go tighter on the lobe separation angle. 110 is a compromise.
Low-mid range is the goal so I would spread out the lobes a bit and pick up a little gas mileage while you are at it. The idle will get even smoother.
If that sounds good to you then ask the cam company to grind you a 112 lobe separation angle.
JMO
-Mark.
Low-mid range is the goal so I would spread out the lobes a bit and pick up a little gas mileage while you are at it. The idle will get even smoother.
If that sounds good to you then ask the cam company to grind you a 112 lobe separation angle.JMO
-Mark.
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Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
I think you will do well with cams close to the size you have selected but you might want to spread the lobe centers a bit for better street manners. The 383 can certainly run well with 110 degree lobes for higher peak power but if HP was your first priority you could (should) even go tighter on the lobe separation angle. 110 is a compromise.
Low-mid range is the goal so I would spread out the lobes a bit and pick up a little gas mileage while you are at it. The idle will get even smoother. If that sounds good to you then ask the cam company to grind you a 112 lobe separation angle.
JMO
-Mark.
Low-mid range is the goal so I would spread out the lobes a bit and pick up a little gas mileage while you are at it. The idle will get even smoother.
If that sounds good to you then ask the cam company to grind you a 112 lobe separation angle.JMO
-Mark.
A 112 LSA will flatten your torque curve and idle a little smoother. I like that Comp XR-282-HR too! Real similar to the second cam I posted with a little less duration on the exhaust and a little less lift. Comp can grind that on a 112 LSA with a couple days lead time.
Last edited by 63mako; Mar 4, 2008 at 08:40 PM.
Thread Starter
Racer
Joined: May 2004
Posts: 288
Likes: 0
From: Tigard OR
I hear talk about the agressive ramp profiles of the Xtreme Energy line of cams causing reliability problems. Is this less of an issue with roller cams versus flat tappet cams?
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,501
From: Little Rock AR
Flat tappet cam designs have to be concerned with the lobes "intensity" so that they do not fail prematurely. The steeper the lift rate with a flat tappet, the more likely it is to fail quickly. Ed Iskenderian published his recomendations regarding what he determined was the limit for "safe" ramp rates for long service life based on his own experience. This intensity limit he published is exceeded on some of the Comp Extreme lobes and we have seen some failures. You can listen to a lot of noise regarding the cam failures and do the math yourself.
-Mark.
