new small block cam
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Pro
Joined: Mar 2005
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From: Rochester PA
new small block cam
Has anyone heard of the 5-7 cam, where it is ground to switch the firing order of #5 and #7. It supposedly gives quicker throttle response, and higher revs. Have just started researching it, so if anyone has any info about it, plz. chime in. Thanks.
Rich K
Rich K
Burning Brakes
Joined: Sep 2006
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From: Spring Grove Illinois
Why Yes It Can.. Cylinders 1 and 6, 8 and 5, 4 and 7, and 3 and 2 are companions: One in the pair is at TDC of the compression stroke at the exact same time that its companion is at TDC on the exhaust stroke. (When an engine such as the new 5.7L/6.1L Hemi has one coil feeding spark to two cylinders simultaneously, the cylinders that share the same coil are always companions.) Because the piston position in each pair of companion cylinders is identical, it's only the camshaft's timing of the valve opening and closing events that determines which cylinder is on the compression stroke and which one is on the exhaust stroke. In other words, the cam decides the firing order. Therefore, any pair of companion cylinders can swap places in the firing order; all it takes is an altered camshaft, plus moving the location of the spark-plug wires on the distributor cap...Lunati has the cam now but it's a 4/7 and it makes 2-3 repeatable Hp on top end...Aint Science wonderful
Burning Brakes
Joined: Sep 2006
Posts: 1,142
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From: Spring Grove Illinois
Here's my opinon... If you've got a stock daily driver under 5,000 rpm, the 4/7 swap probably isn't worth messing with...
If you're into technology and love messing with EFI
and want a new toy to play with to justify individual cylinder tuning, by all means get a 4/7 swap and you might find some power
Thread Starter
Pro
Joined: Mar 2005
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From: Rochester PA
Thanks to all who replied, and especially to Happydad for clarifying that is is 4 and 7 that are swapped, not 5 and 7 (my informant got that one crossed for me). He said his boss just put a 5/7 cam (that's why I posted it as such), in a big block Camaro and got a tremendous HP gain. But now that I know he had the 2 cylinders mixed up (and I was wondering how you could swap 5 and 7 anyway), I am wondering about the "tremendous" HP gain also. End of story, and thread, for that matter.
Rich K
Rich K
