Basically, as a rule of thumb, if your intended use is strictly street, for cruising and maybe as an everyday driver, then 2.5" will be adequate,,,,,,,,,, unless you have 500 HP or more! For the strip, if you have a power plant rated around 425 or more realistic horsepower, then the 3" system would be the way to go. Powerplants with few horses just will not benefit from the larger 3" exhaust although 3" tailpipes showing from behind the rear wheel or under the bumper will make quite an impression. It's been our experience that too big a system will not hurt performance (as long as the primary tubes on the headers are not too large -- Headers do the main 'tuning' of the exhaust), just cost a little more. Now, how about 3.5"? This Huge size is reserved for the really serious,,,,,,, say 600 horses or more!

If you're not sure of the horsepower rating of your powerplant, but have raced at the dragstrip, then any 1/4 mile ET's in the 12.40 - 12.70 range or quicker would benefit from the larger 3" exhaust versus a good 2.5" mandrel bent system.

With powerplants in this horsepower range or up to 575, with a 3" system, you will be able to basically turn ET's equivalent to those with open headers. Imagine! Running through the exhaust and turning low 11's while your competitor is struggling with all the noise and just trying to keep up.

Most 525 HP or so powerplants will never know the difference between 2.5" or 3" on the street for daily driving or cruising, although the big 3" "sewer Pipe" will certainly look great!

Now, IF you're in the 575 HP area, the Big 3.5" pipes might be your ticket. These are some really HUGE pipes and we've had reports of guys loosing their arms in them....just kidding!

Dynomax™ Performance Selection Guidelines

Getting the most out of your exhaust system modifications is easy. Here are some common-sense ways to maximize your horsepower. . . with Dynomax!

A restrictive exhaust creates backpressure in the exhaust system that hurts your vehicle's performance in two ways:

(1) The engine has to work harder to force exhaust gases out of the cylinders.

(2) Engines cannot scavenge burned exhaust gases out of the cylinder efficiently. This leaves exhaust gases in the cylinder to dilute incoming air/fuel mixtures and rob your engine of horsepower.

A common misconception is that the larger the diameter, the better the system. But bigger isn't always better. Systems that are too large in diameter can actually hurt performance. As a general rule, switching to a performance system that is 1/4" to 1/2" inch larger than stock will provide you with the best horsepower increases. To determine which pipe diameters will be best for your system, decide what RPM range your engine will operate at, most of the time. Smaller diameter pipes will produce low- to mid-RPM torque. Larger diameters produce mid- to high-RPM torque.

Bigger isn't always better. Systems that are too large in diameter can actually hurt performance. Improved flow is what you need. Having large diameter pipes isn't what's cool. Going fast and making horsepower is.

Balance Tubes (or 'H' pipes) help to even out the pulses in the exhaust gases and balance the backpressure between both banks of your engine. They not only help improve horsepower, but sound as well. To find the right location to install your balance tube, apply a strip of paint down the front portion of the exhaust pipes. The balance tube should be placed where the paint burns off (bubbles) on the exhaust pipes. Generally, put the balance tubes as close to the headers as possible. The balance tube diameter should be at least 75% of the diameter of the pipes with which it connects.