Headers Effect On Horsepower and Torque - Hot Air

Do, Don't, and RememberDo:* Make an honest and realistic evaluation about what rpm level the engine will benefit most from torque improvements produced by the headers.

* Be mindful of where the engine will be operated a majority of the time, and size headers accordingly, especially for street-driven engines.

* Tend toward smaller, not larger, primary-pipe cross-section areas and work toward longer pipes when space allows.

* Consider tuning exhaust and intake systems at slightly different rpm points for a broader and flatter torque curve.

* Recognize that street-driven engines benefit from mid-rpm torque if overall driveability is a goal.

Don't:* Become misled by using "bigger is better" as a rule of thumb when it comes to primary-pipe size selection unless high-rpm power is the objective.

* Think all primary pipes need to be the same diameter. Two pipe sizes (alternating every other pipe in the firing order) can further broaden a given torque curve.

* Overlook the advantages of stepped primary-pipe headers to broaden a torque curve. It works on the street, too-just ask Hedman Hedders.

* Forget about the benefits of long collectors for low- and mid-rpm torque, especially for street-driven engines.

Remember To:* Retighten header flange bolts often, especially soon after installation of a new set of headers or gaskets.

* Provide adequate spark-plug-wire insulation, knowing that plug wires tend to sag and come into contact with header pipes when exposed to underhood heat.

* Re-check carburetor calibration and ignition spark timing after header installation (even with mufflers). Backpressure reduction can require adjustment to spark and fuel for optimum header benefits.