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09-18-2011, 06:27 PM
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#1
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Join Date: Sep 2006
Location: north jersey
Posts: 1,680
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fact or false
today i was watching the speed channel and they were building a 383 chevy and towards the end of the show they were dynoing the motor and they stated that sometimes by switching spark plug wires 4 and 7 you can make more power. has anyone tried doing this or ever heard of this?
thanks
jim
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09-18-2011, 06:30 PM
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#2
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Co-Founder / Site Admin
Join Date: Jul 2004
Location: Ewing, NJ
Posts: 22,473
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Yes, you can - however it's not that simple. You need a 4-7 swap cam as well, and it won't always make more power. Depends a lot on your setup.
- Justin
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1999 Camry - Beigemobile DD
2002 Suburban - Wife's DD
2004 Grand Cherokee - Not running / Project / Selling?
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09-18-2011, 06:35 PM
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#3
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Join Date: Sep 2006
Location: north jersey
Posts: 1,680
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ahh okay, i figured it was more involved than just switching wires lol they didnt explain it, they just stated that sometimes it makes more power. they also said they have additives to make your exhaust smell like, cherries, and a whole bunch of stuff haha pretty weird
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09-18-2011, 06:36 PM
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#4
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Admin.
Join Date: Aug 2005
Location: Hamilton, NJ
Posts: 20,151
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fact, but everything I've read/been told it the advantage is really for high revving, high hp engines engines. Happy reading
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09-18-2011, 06:43 PM
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#5
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Meet Coordinator
Join Date: Jan 2008
Location: brick/pt. pleasant beach
Posts: 19,341
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It also loads the mains evenly, supposed to help something somehow?
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09-18-2011, 07:19 PM
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#6
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Join Date: Sep 2006
Location: north jersey
Posts: 1,680
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Quote:
Originally Posted by BonzoHansen
fact, but everything I've read/been told it the advantage is really for high revving, high hp engines engines. Happy reading
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a lot of different information out there lol. supposedly the horsepower tv build picked up 33 hp by doing this
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09-18-2011, 08:04 PM
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#7
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Join Date: Mar 2009
Location: Clayton
Posts: 64
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I have a 4-7 swap on my motor ,it's done thru the cam , then firing order. Doesn't really make any more hp, but smoothes the motor and help cooling . It's a little more involved ,and some motor s will make a few more ponies.
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09-19-2011, 06:42 AM
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#8
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Join Date: Sep 2006
Location: north jersey
Posts: 1,680
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Quote:
Originally Posted by dugeman
I have a 4-7 swap on my motor ,it's done thru the cam , then firing order. Doesn't really make any more hp, but smoothes the motor and help cooling . It's a little more involved ,and some motor s will make a few more ponies.
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thanks for the input, thats a nice motor you have there
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09-19-2011, 08:55 AM
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#9
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Join Date: Sep 2010
Location: egg harbor twp south new jersey.
Posts: 229
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Quote:
Originally Posted by Lt1_8U
ahh okay, i figured it was more involved than just switching wires lol they didnt explain it, they just stated that sometimes it makes more power. they also said they have additives to make your exhaust smell like, cherries, and a whole bunch of stuff haha pretty weird
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that was for the barrel of alcohol, it has no smell to it thats what the additive does along with adding lubricant to the fuel.
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09-21-2011, 11:36 AM
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#10
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Sliderule / Moderator
Join Date: Oct 2004
Location: Catawissa PA
Posts: 2,294
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The SBC 4-7 swap is an old school trick used allot when racing classes had intake/carb restictions. One of the issues with a small plenum volume was that the normal firing order resulted in the air flow in the intake to "reverse direction? between the #1/#8 and #2/#7 cylinders (I think they were the one), but baciscally starving the rear cyclinders. Changing the firing order elinimated the reversal from front to back,and made more power, the swap ( ala ford firing order, now LSx firing order ) does also place less stress on the crank, it is also why they sound different/smoother then a older style SBC.
I don't think those scents are ment for unleaded fuel? In the past they wern't. if you ant a nice smell, put CAM2 in the car!
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1) Build it
2) Race it
3) Break it
4) Repeat!!!
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09-21-2011, 12:12 PM
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#11
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Join Date: Dec 2004
Location: Galloway, NJ
Posts: 3,964
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So if it smoothed the engine, allowed it to prevent it from starving the engine, etc. how come GM didn't do it on production SBC?
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Quote:
Originally Posted by BigAls87Z28
Uh yeah, after they surprized buttsecks us at Pearl Harbor?
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09-21-2011, 02:54 PM
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#12
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Join Date: Jul 2008
Location: NJ
Posts: 819
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Quote:
Originally Posted by Blacdout96
So if it smoothed the engine, allowed it to prevent it from starving the engine, etc. how come GM didn't do it on production SBC?
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They did it on the LS1
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09-21-2011, 03:36 PM
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#13
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Join Date: Sep 2006
Location: north jersey
Posts: 1,680
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Quote:
Originally Posted by Pampered-Z
The SBC 4-7 swap is an old school trick used allot when racing classes had intake/carb restictions. One of the issues with a small plenum volume was that the normal firing order resulted in the air flow in the intake to "reverse direction? between the #1/#8 and #2/#7 cylinders (I think they were the one), but baciscally starving the rear cyclinders. Changing the firing order elinimated the reversal from front to back,and made more power, the swap ( ala ford firing order, now LSx firing order ) does also place less stress on the crank, it is also why they sound different/smoother then a older style SBC.
I don't think those scents are ment for unleaded fuel? In the past they wern't. if you ant a nice smell, put CAM2 in the car!
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haha that true, i love that smell! thanks for the info!
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09-22-2011, 02:52 PM
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#14
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Sliderule / Moderator
Join Date: Oct 2004
Location: Catawissa PA
Posts: 2,294
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Quote:
Originally Posted by Blacdout96
So if it smoothed the engine, allowed it to prevent it from starving the engine, etc. how come GM didn't do it on production SBC?
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My opinion on that is because they lose the traditional sound and SBC characterizes Sound, torque curve (along with changing all their tooling such). You do give up some low/midrange torque. If you are running a single plane intake or high rise that increases the plenum volume this does cure allot of the starvation issues.
the 4-7 swap isn't going to give you big gains, all else being equal, let use a fairly stock 250-275HP engine you may pick up 10-15HP at best, it not going to make you run like an LS1, an LS1 has allot of other things that allow it to rev the way it does, light reciprocal weight, short stroke, eliminated crank pressure etc.
__________________
93Z M6 Black: The 385 Lives! Supercharged, 3-core front mount intercooler, GTP heads, 3:73's, Street twin clutch, Jethot Longtubes, Mufflex 4" catback/spintech, S+W cage, Spohn Suspenion, Yada Yada Yada
1) Build it
2) Race it
3) Break it
4) Repeat!!!
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