Might I add that we are tallking to a person who has "glasspacks" on a truck w/a sbc mostly stock??? Not a super gas race car?? Hello- even a set of bulk mufflers from the closeout box in front of the local auto parts store would be better than that. Now if he wants to shave .000878 of of his ET at the nationals in his "truck"... that is different. Bowhay, just pick up some non-glass mufflers & don't get too caught up with the details too much. JMO. Scoot