whatever the collector size is, is usually optimum,"open", w/ some collector tuning(length) if u ran the same size as the collector thru some configuration of pipe and the same size muffler, it still would be below optimum for full h.power for those headers. mine will be 3 1/2" , thru 3 1/2" turbo inserts, w/ a set of 3 1/2" straight thru shortys that only drop the decible level by about 2, figure both will be quieter than a 3 1/2" flowmaster, and flow way better, won`t have but a $120 tied up in all of it, not counting the headers. will be interesting!!-bob:burnout::burnout:
