Interesting article

[LongJohn1980]

Just wanted to see what some of you think about trying the firing order swap on a 409? I had a prominent engine builder suggest doing this on a small block build for my 63 nova. He told me most cam companies will do the custom grinds for the swap. Here's the article I came across today from HOT ROD mag.



"A typical Chevy firing order is 1-8-4-3-6-5-7-2. For the vast majority of applications, this firing order works nicely and there’s probably no need to change it. But in a race application, there are various firing orders that can effectively improve power and reliability in an engine. Typically, there are seven other firing order arrangements which can be used without changing the crankshaft layout on a Chevrolet V8. These firing orders include the following:
1-8-4-2-6-5-7-3
1-8-7-2-6-5-4-3
1-8-7-3-6-5-4-2
1-5-4-3-6-8-7-2
1-5-7-3-6-8-4-2
1-5-7-2-6-8-4-3
1-5-4-2-6-8-7-3

Reher-Morrison has tested the various combinations and found some interesting results. When the firing order is revised to 1-8-7-3-6-5-4-2, you’ll find some power and reliability. Now, if you race a Pro Stock car, this is no secret since the revised order has been in vogue for some time. With the revised firing order, fuel distribution dilemmas are resolved. The engine tends to run cooler, and perhaps just as important, the engine is actually smoother. How much extra power is there? Anywhere between 8 to 10 measurable horsepower. There was once a caveat here though: The average enthusiast couldn’t easily get a cam with the revised lobe positions, but not so today. Reher-Morrison sells such a package (called Big Stick Cams) for Chevy big block/Big Chief head combinations."


Sounds like some could benefit from the cooler engine, plus who dosen't like a few extra ponies!

 

[LongJohn1980]

Sorry, I found this same subject posted from last year, after I posted

 

[models916]

been there done that

I tried to get a cam ground for this. they all said No Can Do.

 

[LongJohn1980]

Just another obstacle for the 409 enthusiast right

 

[SS425HP]

cam changes

I have been told by several cam suppliers that they can do. Roller is easier to get than a flat tappet, though. Dean and I were working on this 2 years ago.

 

[Fathead Racing]

If it were all benifits and no draw backs why didn't GM pick up on this? If the engine runs smoother with more HP and would be more reliable I can't understand why GM didn't jump on this????? Any ideas? What is the firing order on the 2006 small block?

 

[dq409]

soooooo,,,, fred,, lets do it !!!!


And get some of those headers at the same time !!!!


I wonder why GM hasn`t done this,,,??









O,,, never mind,,,, GM and logical ,,,,

 

[models916]

GM did

All new Chevy LT, LS, Vortec engines use the new firing order for some time now.

 

[SS425HP]

Firing order and headers.

Jim, I'm working on the headers. Hard to do from this distance. Can't get the cooperation I need. Working on that part, too. I think I can get them done, just don't know when. Or the cost, either. But I am working on it.

As for the cam, get me some specs you want. Then I'll see what I can do. I was told by a couple cam grinders we could do this. Sometimes they say one thing, but do another. I was at the PRI show in December at Orlando. I know several guys that were promised product for the coming year from different Mfg. They got nothing when crunch time came. I make no promises, as I make no cams. All I can do is try to get someone to do what THEY say. Get me some specs and we will go to work.