496 ho/headers to lean?
 

Has anyone experienced or heard of headers leanning out a 496 ho to the point that you loose power instead of gaining power.
Here is my situation, after installing headers I lost @ 700 RPM checked fuel preasure its 48lbs at idle 50lbs at 4000 RPM, it has a upgraded regulator because it has Raylar 525 kit,timing is 22@4000 RPM throtlle is 100% both visual and at scanner, fuel filter is good and clean.
I talked to lightning( HEADERS) and he thinks I may be too lean and the knock sensor is causing timing to pull back, but ray says 22degrees is normal @4000 RPM.
I only run at Havasu and live 300 miles away so I can't experiment to much. I will try a local lake with current situation and see if richening makes a difference, but they have speed limits there so it may not help me.
Any leads or thoughts are highly welcomed.:signs069:

BobL has dyno'd and worked with that exact setup and can assist you. I do know that there was no lean out issues however.
Try PMing him.
Dave

thanks ,I have seen that he has experience with 496.

More than likely your in gaurdian mode which will not allow it to go over ~4300rpm.
Do you have access to a scanner (Diacom)
You may have left a sensor (exhaust manifold temp) unplugged or something along those lines.
Dave

Dave's right. The lightnings won't lean it out that much. You're going into guardian mode. Get a scanner on it to determine what is going on. Probably an exhaust temp sensor or water pressure.

I do have Diacom and everything is OK no alarms no codes. Now,the plugs are real clean even with the 525 raylar kit it was just a little on the fat side. Now the question is if the knock sesor is detecting detonation will that cause the sam thing ?

You should be able to see any knock retard with Diacom. Check the %power available. I bet when you hit around 4300 RPM it is being reduced to 90% or less. If so you should be able to determine what is triggering it. From what I've seen it can do this and not set a guardian event in fault history, or audible alarm. I had a similar scenario that was triggered by an IAC that went bad. It would only go to 90% power above 4300 RPM.

That's one thing that puzzled me as well, it always said 100%.
Havin said that, even if it was pulling back on timing,fuel or what ever it does to lower the power the Diacom should have read less power.
I know that removing them and putting OEM back is one way to see if thats the problem, but it's some work to do that.

I have triple 496's and installed CMI's and now am having the same problem but the difference is it is only on one engine. I am convinced it is a sensor doing it but I too have not had a chance to find it. Throw out the idea of a lean condition as my other two engines are not having the same problem. Once I figure mine out, hopefully this weekend, I will let you know.

At least you got another motor to swap whatever you might think to be the culprit, but I can't put in the water untill next week and fatten it up and see what happens.