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Author Topic:   Comp Cams
Dirt Full Roller

Total posts: 62
posted April 09, 2003 09:42 PM
I was flipping thru my comp cams wish book, and noticed that they have new grinds for the SBC that change the firing order from 18436572 to 18736542. What is the reason behind it, is it to keep 5 and 7 from crossfireing? or what. Steve this one is probally for you, unless someone else can shed some light!

Dirt Freak

Total posts: 467
posted April 10, 2003 08:45 AM
There is actually another firing order besides the one that you posted , but I don't remember what it is . These different firing order's are used most commonly in drag race application's , usually in car's that are spraying massive NoS load's . Part of the reason for this is to allow each cylinder a little extra cooling time before each charges come in . This has not gone anywhere in any other form of racing though . In fact , to the best of my knowledge WC teams have tried this and they have stayed with the std. firing order . I have personally never done any testing , but from what Dave Crower has told me , I'd be wasting my time .


Hendren Racing Engines
Rutherfordton , NC

Dirt Freak

Total posts: 237
posted April 10, 2003 09:45 AM
Might make a great cam for a claimer motor. Can you imagine the confusion that would cause someone that bought a motor for $425? LOL...

The Rascal
Dirt Roller

Total posts: 13
posted April 10, 2003 05:53 PM
It "fixes" some of the 4-3-6-5 cylinders all pulling from the same plenum space at nearly the same time...switching 4 & 7 helps but still offers the least amount of compromise...the big thing that it helps is engine...therefore racecar acceleration...and it's best applied in a single plane restricted motors it can make a "worth it" difference...they sound pretty cool


Dirt Forum Champ
Total posts: 620
posted April 10, 2003 09:51 PM
ford changed the firing order on their small blocks a few years ago to relieve the stress on the main bearings caused by 2 cylinders on the same rod journal firing sequentially. i'm not sure if this applies to chevrolets, but it might be something to consider.

Dirt Maniac

Total posts: 110
posted April 11, 2003 10:17 AM
This is very interesting and I would like to hear more input on it if anyone else has anything to add....towman

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