John and every one else; Thank you for the education. I have a 100% 76 NYB with 440 (no lean burn that year on 440s) that just happens to need a new exhaust. I'll probally have 'em put a crossover and dual exhaust is there an other way than waiting for the discoloration of the pipe to know where to put the H pipe? Joe --- John M Bittner <jmb@xxxxxxxxxxxxx> wrote: > Joe, It all has to do with flow dynamics. One...