Will headers make a diffrence?

Question

CAI already installed, going with dual exhaust.

2001 mercury cougar v6 2.5

Answer 1

on my 69 windsor 351, i didn't notice a difference.  but was told that they made it better.

Answer 2

Probably one of the least cost effective mods for that car. Your car lacks torque. The stock manifolds are hard to beat for making torque. If I had your car, I'd be looking for an engine out of an SVT Contour.

Answer 3

The difference will likely be incremental, but when you upgrade the intake as well, then there will be something more noticeable.