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This past Sunday I watched an show where the the guys on the show switched the firing order of a 350 chevy between #4 and #7 cylinder. To do this they put a new cam in and switched the two plug wires going into the distributer. On the dyno this gave the engine nearly 40 extra HP!!! They said this occurs because the engine becomes more efficient in the firing order. Does PCM already do this? What are your thoughts? As far as HP goes, this seems like one of the the cheapest out there for our boats.
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RE: Switching firing order of #4 and #7 cylinders
This is called the 4/7 swap. I saw the same show and was intrigued about it as well. I think a good amount of HP gain was because of the cam itself rather than the 4/7 swap. -
The Corvette LS1 engine has the “4/7 Swap” firing order (1-8-7-2-6-5-4-3) from the factory. (Note that 2 and 3 are also swapped in that engine). Horsepower gains are small if nothing else is changed except the firing order. Here’s a link to Lunati’s cam:
http://www.holley.com/HolleyNews/article.asp?ID=37Comment
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Interesting. I might have to look more into that when it comes rebuild time.2018 SAN 230
1981 Ski Nautique
Sold - 2011 Sport 200V
Sold - 2000 SANComment
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Yep!2018 SAN 230
1981 Ski Nautique
Sold - 2011 Sport 200V
Sold - 2000 SANComment
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Very cool- not many older boats with them. Do you have a page with pics either here or on CCFan? I couldnt find one.1990 Ski Nautique
NWCTComment
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I would have posted earlier... but I've been gone all weekend and just got back to check pn! Here ya go!
I have plans in to rebuild it and paint it all pretty in the next few years, hehe. Those were taken a few years ago when I was changing the impeller.2018 SAN 230
1981 Ski Nautique
Sold - 2011 Sport 200V
Sold - 2000 SANComment
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