Headers SHOULD absolutely, positively work.
But on these engines, sometimes the results are totally lame. I haven't spent much time researching this but I keep seeing similar results
and results trump theories EVERY TIME, in my mind.
The majority of power gains with headers on the Gen III Viper engines seem to be on the so-so to low side. And OldColt's truck isn't the only viper powered vehicle that was "Non-Responsive" towards headers. But his engine was "special" and wouldn't respond to S.F.A. !!! Well, until i
t was forced to with a new camshaft installation.
Threads in the past on these forums, have some guys saying they feel headers are a total waste of money. Then there are guys that have had some measured, even decent gains, in both torque and horsepower. So, there you go...
Manufacturer's claims are often always very positive (no surprise there) but, for the most part, I haven't seen anything too outstanding yet.
With the latest round of mods on my personal vehicle, I may have to break down and retire the o.e.m. manifolds, I guess I'll have to wait and see.. If I do, I'll favor the smaller primary pipes for best results at our altitude.
If I was strictly RACING my truck, for example, I'd be using headers, without a doubt.