> I've installed headers before on stock engines and have never seen a
> downside to them.
Headers CAN hurt performance-if they are the wrong length and diameter.
Stock to mildly warmed over street engines need small diameter, long tube
headers to make torque.
The big diameter only helps for highly modified, high rpm engines that
really have a lot of volumetric efficiency-they move a lot of air.
Engines are nothing more than air pumps. I remember from my younger days the
hot headers for 318-340 Mopars had 1-5/8 diameter tubes-today, people would
say, WHAT? You gotta have 3 to 4 inch pipes! Yup, for sound. Headers really
woke up the old 318 2 bbl in a heavy old Charger. But I'd bet the pipes were
small and the collectors were real long. Perfect for making torque, which
those things needed. Just dual exhaust with stock mufflers helped a bunch. I
know, I had a few of them. As Scotty would say, "You cannot change the laws
of physics."
A great example is the guy who buys a new Harley. What's the first thing he
does? Yup, big diameter straight pipes. Sounds great, but I'll bet he loses
10 hp and a bunch of torque on the bottom end and midrange, and has no top
end, because the carb is way too lean and the cam too small to make any
power with the increased flow he got. And Harleys can't afford to lose ANY
power. But, it sounds better, so it is "faster". Slap some small diameter,
long pipes on it, and watch the hp and tq jump in the bottom and midrange,
right where a HD runs. They don't make any power over 5k (stock) anyway, and
won't last long there, either.
Jon
STL MO
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