it varies on the manifold and engine. if it helps move air it will increase horse power, if it doesnt, torque.
eight hp
5 to 9 horsepower about 7 horsepower i felt a big change of horsepower in mine
Maybe 10
3 to 8 maybey 10 but not likely
about 5 - 10 hp
cat back? 12hp/12ft-lbs.
Not enough to even notice.
Not a significant difference all the dual exhaust does is cut back pressure ergo the louder sound
by itself, not much, not enough to notice, if you go with a performance carb and air filter as well as the exhaust you will see a lot of difference.
Very little. It is better to have duals instead of single as it is harder for the car to breath. But it can add 5-10 horse.
add intake chip from eBay and put an exhaust.
Several things can add horsepower to your truck. A free flow air filter, different exhaust, or computer chip change can all help get more horsepower.