[jhv48]

For all the guys with Roush motors that have changed from the Street Avenger vacuum secondary carbs to mechanical secondary carbs, that is just the first step in improving the breathing of these engines.

You will find a whole bunch more horsepuppies if you then replace the restrictive sidepipes with ones that allow the motor to exhale properly. My stock SPF sidepipes measured about 1 3/4 inches on the inside baffle. My new ones are 3 inches. Slide a mirror inside yours and you will see how restrictive the stock ones really are.

They need to inhale and exhale properly. Just replacing the carb is only half the fix!