Vacuum operated exhaust cutout?

[86regalss]

are these available? I want something like this that opens at the higher rpms. I dont really want electric cutouts. Also I want something that seals good and doesnt sound like an exhaust leak.

[b-man]

Vacuum operated cutouts incorporated into the mufflers:

http://forums.performanceyears.com/forums/showthread.php?t=533408

Should be available here:

http://www.waldronexhaust.com/