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  #1  
Old 01-24-2001, 04:42 AM
cdignition cdignition is offline
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Hi all knowing mopar guys...i have a question sure to stump the best on this board...I understand that changing the firing order can have some positive effects on power output...all that is needed is a custom ground cam to match the new order and swap the plug wires to the distributor....can anyone tell me whats optimum?....plz dont tell me factory stock is, cause i know it isnt...Enlighten me...
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Old 01-24-2001, 04:56 AM
GTXMONTE GTXMONTE is offline
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This is Pro-Stock technology and usually it is number 4 and 7 that get swapped in the firing order. There are others but the above is the most common. While this is worth a few HP, it is really not worth the added cost unless you are having a one off cam custom made. It takes a custom billet as an off the shelf billet does not have the meat in the right spots. You can figure one of these cams to be a minimum of $500.00. The one I had ground for my TS motor with modified firing order was $675.00.

Monte Smith

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SURGEON GENERALS WARNINGrag Racing is highly addictive, and may impair your ability to make rational decisions.
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Old 01-24-2001, 05:02 AM
rat roaster rat roaster is offline
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A friend of mine Warren Robins talked about this years ago to me and also about crossing the headers over on a stock fireing order so as to utilise the cylinders exhaust to help create a vacume or in the headers so to speak. The one cylinders exhaust would draw out the exhaust on the other one and so on. I dont remember much about the conversation but I thought he said they had crank problems with the cam deal. I will have to talk to him again to refresh my memory. He use to build fuel hemi engines for cars and boats . The last time I seen one of his engines was in the Rated X blown fuel jet boat. My brotherinlaw Dave Gionnette drove the boat. Warren lives in California so I will have to call him if you dont get any answers on this from someone else . This fellow ran hemis in the 1960s and up so he is quite versed on the hemi.

[This message has been edited by rat roaster (edited January 23, 2001).]
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  #4  
Old 01-24-2001, 07:12 AM
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rumblefish360 rumblefish360 is offline
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I have had these talks with older drag racers. This is "MAD SCIENTIST AREA" and can quickly confuse alot of people.
This kind of stuff requires DEEEEP pockets, mad research and a twisted brain.

Welcome to the club!

At this level of thinking you can now be engineering your own eng. for whatever you desire.
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Old 01-26-2001, 02:38 AM
Dragracerr Dragracerr is offline
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GTX is well versed in his response, the cost per gain is negligible for anything less than Pro Stock, Comp Eliminator etc. One will see bigger gains in Siamese port configurations and less on Spread port. In the theoretical world this sounds like a must do for the Siamese port engine, but in the practical world there is usually more bang for the buck in many different areas.
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Old 01-27-2001, 01:03 AM
kchristopher kchristopher is offline
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Quote:
Originally posted by rat roaster:
A friend of mine Warren Robins talked about this years ago to me and also about crossing the headers over on a stock fireing order so as to utilise the cylinders exhaust to help create a vacume or in the headers so to speak. The one cylinders exhaust would draw out the exhaust on the other one and so on. I dont remember much about the conversation but I thought he said they had crank problems with the cam deal.

This is what a true tri-y header will do. Doug Thorley's website has an article on it. Production tri-y headers don't work quite as well, but they don't have tubes going from one side of the engine to the other either.


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  #7  
Old 01-28-2001, 03:32 AM
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Christopher Christopher is offline
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Monte is right.Actually I first heard about this reading a Reher-Morrison ad in National Dragster and it got me thinking as well.But from what I understand,it's on average only worth 10-15 Hp,which is not enough for me to spend $600+ dollars on a new cam.Now in Monte's case,this might be worth it,but not for the average racer like me.Maybe Monte can enlighten us on the actual Hp increase.
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Old 01-28-2001, 05:13 AM
GTXMONTE GTXMONTE is offline
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The guy that ground my cam said it was worth about 25HP. That is not worth it to me, but as I was having a custom cam ground anyway, he said we might as well. An off the shelf billet would not work in my engine because we have moved the lifter bores and changed the angles on them to improve geometry, plus the journals are 2.5in diameter with roller brgs. Steve Lowe at LSM is the guy who did the cam and lifter bores, he does work for lots of Pro-Stock teams, so whatever he said would help, I let him do it.

Monte Smith
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