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RE: 4-7 firing order cam swap

To: <richk@mercurylink.net>, <land-speed@autox.team.net>
Subject: RE: 4-7 firing order cam swap
From: "Dave Dahlgren" <ddahlgren@snet.net>
Date: Sat, 13 Mar 2004 05:38:53 -0500
Most Dynos are +- 1% at best not counting variatins in the cell during a
test...
3-20 hp out of how much?
If you swap 4 & 7 to eliminate the 5-7 combo of firing together you replace
it with a 4-2 combo.
In a 700 hp engine the best you can measure is +- 7 hp so 693 and 707 hp are
the same number unless you make around 10 pulls and average them.
I don't think you can have a 90 degree crank in a V-8 that does not fire 2
cylinder next to each other..
The only thing i can imagine you could do with this is swap some torsional
twist in the cam for some twist in the crank.
Next..
Dave
> -----Original Message-----
> From: owner-land-speed@autox.team.net
> [mailto:owner-land-speed@autox.team.net]On Behalf Of
> richk@mercurylink.net
> Sent: Friday, March 12, 2004 8:04 PM
> To: land-speed@autox.team.net
> Subject: 4-7 firing order cam swap
>
>
> Twice I've run across this in the past month but haven't seen any
> technical discussion on the subject. Swapping chevy firing order giving
> claimed increase of 3 - 20 HP in a simple A - B cam comparison. What's
> being gained here? How does exhaust or intake design affect this?
>
> RichK






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