Mark VIII Frequently Asked Questions Exhaust         List of Categories         What size tubing is stock? What's this 'true dual' system on the LSC models? Can I put headers on my car? What upgrade options are there? Can I just replace the mufflers? What's the best muffler? Can I just cut off the mufflers and put in straight pipe? Why can't I just run two separate pipes all the way from the front to the back? Will removing my third catalytic converter cause a Check Engine Light? Is that really a catalytic converter in the middle of the car, or is it just a resonator? What size tubing is stock? 2.25" tubing is used on all Mark VIII models. Top What's this 'true dual' system on the LSC models? The LSC exhaust goes from the manifold/pre-cats, into a dual in/dual out third catalytic converter, maintaining two separate pipes. It was worth 10 HP and 10 TQ, according to Ford. Top Can I put headers on my car? Yes, but it's not easy or cheap. Longtube headers are reported to show the greatest difference in horsepower and torque, but there are no readily available headers for our cars. They are typically custom built. Top What upgrade options are there? Many members have upgraded their exhausts from the front cats all the way to the back. Typically, a full dual exhaust, with either a H or X crossover installed near the front of the system, is installed with 2.5" tubing throughout the system. New mufflers are typically part of the equation as well. Top Can I just replace the mufflers? Sure, you can replace just the mufflers, for a different sound. It hasn't been proven to provide much difference in horsepower or torque, but many people are only looking to improve the sound of their car's exhaust. Top What's the best muffler? There is no 'best' muffler, only the one that meets YOUR particular needs. What some people may consider 'muscular and powerful sounding', others may find annoying and droning. The best flowing mufflers are typically those that have a 'straight through' design, such as Dynomax UltraFlo or Magnaflow mufflers. 'Turbo' mufflers typically have two 180 degree turns internally, and are often much more restrictive. Flowmaster mufflers have often been reported as creating a drone in the exhaust, particularly at highway speeds, but again, this is a personal preference. Top Can I just cut off the mufflers and put in straight pipe? Many of the people who have tried this have reported excessive droning and some low end torque loss. It is not typically recommended. Top Why can't I just run two separate pipes all the way from the front to the back? Using a crossover pipe with true dual exhausts has been shown to improve horsepower and torque throughout the powerband. It also provides a more even exhaust note. Top Will removing my third catalytic converter cause a Check Engine Light? It should not, on any year model Mark VIII. Top Is that really a catalytic converter in the middle of the car, or is it just a resonator? It is described in technical manuals and parts listing as a catalytic converter. Removing it may violate federal regulations regarding emissions equipment. Top Was this page helpful?     F.A.Q Software supplied free of charge by PerlScriptsJavaScripts.com Copyright 2001-2010 Calvin Louie/www.markviii.org. Use without permission prohibited.