Exhaust Bore.

[Pezzer]

With so many GQ owners here I was wondering what is believed to be the optimum Bore size for a standard TB-42E with extractors?
Tip wise I have found the ground facing bend works well when launching and retrieving boats as it provides an airlock so water does not enter the muffler box.

[threedogs]

Yeah those "dump" tips are popular, on a Petrol you'd find that 2.5" works well
unleashing the beast within, combined with a set of headers your should gain both
in power and at the Bowser. Anything bigger will give a hum or droning sound at HWY speeds,
which is very annoying, combine the 2.5" with a sports muffler to give it a bit of a note, happy days