Hi Has to do with the equalization of pressure...don't know technical answer but it sure works. Some guys say to put some paint on the pipes first, run the car, and then put the equalizer were it was hottest. Jan ----- Original Message ----- From: "Joe Bachan" <jbachan@xxxxxxxxxxxxxxxxxx> To: <mailing-list@xxxxxxxxxxxxxxxx> Sent: Thursday, February 05, 2004 3:54 PM Subject: Re: IML: Two 75 Imperial Questions -- Vinyl Top Removal and Cam Profile > Pardon my ignorance but how does tying the two exhaust > pipes of a dual exhaust system together with an 'H' > pipe improve performance? > joe > --- dardal@xxxxxxxxxxxxxxx wrote: > > Quoting Brad Hogg <roadhogg@xxxxxxx>: > > > > > Regarding the H pipe. My muffler guy suggested if > > he were to convert my > > > single exhaust car to dual that he would use > > everything as is ans simply add > > > a second pipe to the right side. He would just > > create a cut out in the > > > elbow of the... > >