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4 and 7 Firing Order Swap (Camshaft)

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Old Aug 1, 2007 | 03:37 PM
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4 and 7 Firing Order Swap (Camshaft)

Anyone ever swapped 4 and 7 on an lt1 350 and made any power or made the engine smoother? I think it would help with our restrictive intakes.
Old Aug 1, 2007 | 08:49 PM
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If they were the same price as a regular cam, they would be worth trying. The timing swap they do on 4/7 just moves the fuel distribution problems to a different pair of cylinders in the firing order.

For a typical street car, you won't see any difference in performance if you had identical cams. One being a normal cam and the other being a 4/7 swap.

For the increased cost to have a 4/7 swap cam, you'll be better off investing your money into something else.
Old Aug 1, 2007 | 08:59 PM
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well I was considering it because it allows 4 and 2 to fire together at the right front near the throttlebody instead of 5 and 7 together at the left rear. seems like the air would have an easier time getting to 4 and 2 at the front?
Old Aug 3, 2007 | 07:09 AM
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Horsepower TV did this swap on a dyno mule and it gained 30 hp using the same grind.
Old Aug 3, 2007 | 04:54 PM
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Originally Posted by ulakovic22
Horsepower TV did this swap on a dyno mule and it gained 30 hp using the same grind.
Any more info on the engine used? what kind of intake was it and how much power was it making?
Old Aug 3, 2007 | 07:19 PM
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I think bret said he could do the cams. But something about tuning issues. Its been talked about a few times before.
Old Aug 3, 2007 | 07:29 PM
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This idea has floated around for years. It would be SOP if gains anywhere near 30hp were possible. All the cam grinders can do the cam.

Rich
Old Aug 3, 2007 | 10:01 PM
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Originally Posted by RRR
Any more info on the engine used? what kind of intake was it and how much power was it making?
I searched and searched for more info but couldn't find anything. It was done to their stock chevy 350 dyno mule when they first got their DTS engine dyno installed. I did however find lots of info on it and the gains really depend on displacement. Instead of retyping a bunch of stuff, here is one of the articles I found. Basically the 30 hp I said above is either a crap number that I remember or they did other stuff to the motor at the same time and I just remembered incorrectly.

http://www.hotrod.com/techfaq/113_07...ams/index.html

Last edited by ulakovic22; Aug 3, 2007 at 10:04 PM.
Old Aug 3, 2007 | 10:35 PM
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In the link it was 2-3hp on a BBC.

Rich
Old Aug 3, 2007 | 11:00 PM
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yeah, I read that article too. but to be clear I am looking at it more from a standpoint of the lt1 manifold lacking plenum volume and having cylinders 4 and 2 firing at the front of the manifold would be better (more air shorter distance) than 6 and 7 at the left rear. wouldn't doubt this wouldn't be worth the cost on an engine with a better intake but it does make me think it might be on an lt1.
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