[coyled]

Ole yeller, The reason most exhausts go down to a collector and back up is for low end torque. Most cobras in race applications go down to a 3 1/2 inch collector and out to a 4 inch open pipe. This has the effect of sucking the exhaust gas thru a lower rpm's, hence more torque. I left mine at 4 inches from collector thru the open pipes for 2 reasons. I don't need any more low end torque and the slip fit configuration for my street and race pipes was easier. My headers are stepped up 8 inches away from the heads from 1 7/8 to 2 inch. Now, I thought I should have a bigger pipe like 2 1/8 but the builder said in testing they lost low end power and did not pick up top end power with the cup style 358ci motors like mine. Lots of technology there guys, not sure I understand it all. scott