Who is doing 4 - 7 firing order swap.
09-26-2006 | 11:06 AM
#1
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From: 29°50'49.74"N 95° 5'17.55"W.......TEXAS
Who is doing 4 - 7 firing order swap.
Saw this on horsepower tv saturday. 30hp gain on a small block with identical cam profile. Well almost, they did say the new cam was laser cut.
They swapped the position of the lobes in order to change the firing order. Works on BBC also.
This is what Lunati says
Lunati 4/7 Swap Cams
10/14/2003
Memphis, TN--LUNATI, The Racer’s Company, is proud to announce the availability of their new line of 4/7 SWAP Camshafts for small and big block Chevrolet solid roller applications.
The 4/7 firing order SWAP configuration decreases crankshaft deflection, delivers a smoother torque curve, and aids acceleration. 4/7 SWAP Camshafts also provide an incremental horsepower gain in the engine. 4/7 SWAPS were track tested in a wide variety of applications and all results were improvements over the standard firing order. Dyno results have shown a 3 to 12 HP gain with the SWAP. The only change that must be made to the engine is to swap the 4 and 7 plug wires to reflect the alternate firing sequence. 4/7 SWAP Cams are available in most popular grinds and on custom ground camshafts.
For more information contact LUNATI, 11126 Willow Ridge Drive, Olive Branch, MS 38654. Telephone: 901-365-0950. Or visit us on the web: www.lunaticamshafts.com
They swapped the position of the lobes in order to change the firing order. Works on BBC also.
This is what Lunati says
Lunati 4/7 Swap Cams
10/14/2003
Memphis, TN--LUNATI, The Racer’s Company, is proud to announce the availability of their new line of 4/7 SWAP Camshafts for small and big block Chevrolet solid roller applications.
The 4/7 firing order SWAP configuration decreases crankshaft deflection, delivers a smoother torque curve, and aids acceleration. 4/7 SWAP Camshafts also provide an incremental horsepower gain in the engine. 4/7 SWAPS were track tested in a wide variety of applications and all results were improvements over the standard firing order. Dyno results have shown a 3 to 12 HP gain with the SWAP. The only change that must be made to the engine is to swap the 4 and 7 plug wires to reflect the alternate firing sequence. 4/7 SWAP Cams are available in most popular grinds and on custom ground camshafts.
For more information contact LUNATI, 11126 Willow Ridge Drive, Olive Branch, MS 38654. Telephone: 901-365-0950. Or visit us on the web: www.lunaticamshafts.com
09-26-2006 | 01:25 PM
#2
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From: On A Dirt Floor
Re: Who is doing 4 - 7 firing order swap.
If the new cam was "cnc'd" and the other wasn't , then that makes that hp comparison/statement crap. 
It can and does benefit, but it's not a huge leaping gift from the hp Gods.
Anybody that is running a serious effort solid roller Chevrolet should atleast talk to there cam designer about it when replacing cams. If you don't need a new cam, then don't sweat it.
It can and does benefit, but it's not a huge leaping gift from the hp Gods.
Anybody that is running a serious effort solid roller Chevrolet should atleast talk to there cam designer about it when replacing cams. If you don't need a new cam, then don't sweat it.
09-26-2006 | 03:47 PM
#3
MarineKinetics
Joined: Oct 2002
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From: Rochester, NY
Re: Who is doing 4 - 7 firing order swap.
Mark,
We have used the 4/7 swap in numerous solid roller configurations and are pleased with the results. That being said there is always a mixture of fact vs. fiction where technology meets marketing. While it is fact that swap cams will show power gains in very specific applications, there is differing information as to why.
I can tell you most 4/7 cores are ground only to accept lobes in the upper duration levels. (255º+ @ .050" and up) This is a strong indicator as to the RPM range the swap cams are effective.
Secondly, in all the testing I have seen or participated in, the swap cams have only worked in common plenum, wet flow, intake manifolds. While the notion of reduced "crankshaft deflection" has validity from a durability standpoint, all the evidence I have seen points to uniformity of mixture in upper RPM ranges, as being the power producing element.
The upside, there is no "trade off" or "downside" to the 4/7. The core up-charge is approx. $20.00 and you use all standard components relative to the performance level desired.
Most documented increases are in the area of 1%-2% above 6000 RPM. I would be inclined to believe there was a touch of optimistic "marketing" involved in the 30 HP increase in the SBC cited on HP TV.
Fact is, if you have the correct mechanical configuration, and are running the necessary RPM levels, there is no reason to leave the 4/7 option on the table. As incremental performance increases get harder to find it can be $20.00 well spent.
Bob
We have used the 4/7 swap in numerous solid roller configurations and are pleased with the results. That being said there is always a mixture of fact vs. fiction where technology meets marketing. While it is fact that swap cams will show power gains in very specific applications, there is differing information as to why.
I can tell you most 4/7 cores are ground only to accept lobes in the upper duration levels. (255º+ @ .050" and up) This is a strong indicator as to the RPM range the swap cams are effective.
Secondly, in all the testing I have seen or participated in, the swap cams have only worked in common plenum, wet flow, intake manifolds. While the notion of reduced "crankshaft deflection" has validity from a durability standpoint, all the evidence I have seen points to uniformity of mixture in upper RPM ranges, as being the power producing element.
The upside, there is no "trade off" or "downside" to the 4/7. The core up-charge is approx. $20.00 and you use all standard components relative to the performance level desired.
Most documented increases are in the area of 1%-2% above 6000 RPM. I would be inclined to believe there was a touch of optimistic "marketing" involved in the 30 HP increase in the SBC cited on HP TV.
Fact is, if you have the correct mechanical configuration, and are running the necessary RPM levels, there is no reason to leave the 4/7 option on the table. As incremental performance increases get harder to find it can be $20.00 well spent.
Bob
09-26-2006 | 03:59 PM
#5
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From: E-Dock
Re: Who is doing 4 - 7 firing order swap.
I ran a 4-7 swap last yr and was very happy with it. I was told that this also helps with fuel distribution, but I have no idea.
What about the LS 1 firing order cams??
What about the LS 1 firing order cams??
09-26-2006 | 04:15 PM
#6
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From: On A Dirt Floor
Re: Who is doing 4 - 7 firing order swap.
Originally Posted by RLW
For what it's worth, the Vortec HP3's run a 1-8-7-2-6-5-4-3 firing order.
09-27-2006 | 08:58 AM
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From: 29°50'49.74"N 95° 5'17.55"W.......TEXAS
Re: Who is doing 4 - 7 firing order swap.
Originally Posted by rmbuilder
Mark,
We have used the 4/7 swap in numerous solid roller configurations and are pleased with the results. That being said there is always a mixture of fact vs. fiction where technology meets marketing. While it is fact that swap cams will show power gains in very specific applications, there is differing information as to why.
I can tell you most 4/7 cores are ground only to accept lobes in the upper duration levels. (255º+ @ .050" and up) This is a strong indicator as to the RPM range the swap cams are effective.
Secondly, in all the testing I have seen or participated in, the swap cams have only worked in common plenum, wet flow, intake manifolds. While the notion of reduced "crankshaft deflection" has validity from a durability standpoint, all the evidence I have seen points to uniformity of mixture in upper RPM ranges, as being the power producing element.
The upside, there is no "trade off" or "downside" to the 4/7. The core up-charge is approx. $20.00 and you use all standard components relative to the performance level desired.
Most documented increases are in the area of 1%-2% above 6000 RPM. I would be inclined to believe there was a touch of optimistic "marketing" involved in the 30 HP increase in the SBC cited on HP TV.
Fact is, if you have the correct mechanical configuration, and are running the necessary RPM levels, there is no reason to leave the 4/7 option on the table. As incremental performance increases get harder to find it can be $20.00 well spent.
Bob
We have used the 4/7 swap in numerous solid roller configurations and are pleased with the results. That being said there is always a mixture of fact vs. fiction where technology meets marketing. While it is fact that swap cams will show power gains in very specific applications, there is differing information as to why.
I can tell you most 4/7 cores are ground only to accept lobes in the upper duration levels. (255º+ @ .050" and up) This is a strong indicator as to the RPM range the swap cams are effective.
Secondly, in all the testing I have seen or participated in, the swap cams have only worked in common plenum, wet flow, intake manifolds. While the notion of reduced "crankshaft deflection" has validity from a durability standpoint, all the evidence I have seen points to uniformity of mixture in upper RPM ranges, as being the power producing element.
The upside, there is no "trade off" or "downside" to the 4/7. The core up-charge is approx. $20.00 and you use all standard components relative to the performance level desired.
Most documented increases are in the area of 1%-2% above 6000 RPM. I would be inclined to believe there was a touch of optimistic "marketing" involved in the 30 HP increase in the SBC cited on HP TV.
Fact is, if you have the correct mechanical configuration, and are running the necessary RPM levels, there is no reason to leave the 4/7 option on the table. As incremental performance increases get harder to find it can be $20.00 well spent.
Bob
Thanks for the reply Bob, I was looking into this for our UMP late model engines as a possible "cheap" upgrade during the next freshen up. I read a reply you made on another forum in 2004 on this subject. I think it looks like a sensible option for the rpm's that we are turning in our 427 smallblocks.
I am also looking to add Pan-E-Vac systems as I think that is also an inexpensive "incremental" upgrade that will possibly also help with the alcohol contamination.
You dont see Pan-e-vac systems too much any more and I understand that they dont work with exhausts that have mufflers due to backpressure, is there any other reason that they are raely used any more. So far we dont have to run mufflers at most of our local tracks.
09-29-2006 | 07:54 AM
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From: franklin,Tenn.
Re: Who is doing 4 - 7 firing order swap.
I did a 4-7 swap last year. I didnt see the type of hp gains your talking about. The worst thing about it was waiting for a quality core so I could run a stock distributor gear. I run solid rollers and the motors run 57 to 6300 rpm. These are 540ci. 668tq@5200 720hp@6300 on pump gas. The cams i had made are exactly the same as the ones i took out, only difference was 4-7 swap. On the dyno everything was the same as far as timming and jetting. In my case it wasnt worth the effort for a couple lbs. of torque. Brian
