jfnar,

Since you appear to favor Flowmaster mufflers here's a link to what Flowmaster has to say on the subject, quoted on a Mustang forum.

https://www.stangnet.com/mustang-fo...compared-to-regular-dual-exhaust.605983/

Here's some really well documented performance data on exhaust balance tubes:

http://garage.grumpysperformance.com/index.php?threads/x-or-h-pipe.1503/

It's from the Performance section of the Chevy Talk forum.

Last edited by yar; 02/20/2017 4:03 AM.
Ray