Jay Honeck wrote:

Hmmm. I thought that new "performance exhaust" system for Cherokees and
Skyhawks had to be "x" number of inches (feet?) long in order to "tune" the
exhaust, in order to increase horsepower "x" percent?

Tuned headers work by the fact that, if you take tubes that are between 32" and 36"
long and hook one end of each to the exhaust port of the engine and the other end to
a collector tube, the flow of the exhaust from the first cylinder to fire will help
pull the exhaust out of the second cylinder to fire. I was told that the length of
the exhaust system after the collector doesn't matter. You can reduce the length of
the tubes in the header by adding bends; conversely, if you have to bend the tubes
for clearance reasons, you have to reduce the length. This is why most automotive
tuned headers look like pretzels.

George Patterson
If you don't tell lies, you never have to remember what you said.