Tri-Five Chevy Header-Back ExhaustNew from American Racing Headers are our 1955 1957 Tri Five Chevy Header Back Exhaust Systems. Designed with durable . 065 wall tubing and your choice of our rear or side exit tail pipes, our 3" H Pipe, and our Pure Thunder Series mufflers. Pair this system with a set of ARH Tri Five Headers by clicking here. We are proud to build these systems at American Racing Headers in our Research and Development facility with aerospace grade T 304 stainless