Average exhaust port diam, port length, and port flange diam on the china girl engine

[Jayraye39]

The second one looks pretty good, I've tried one like this and found that a larger belly section at 100mm dia works even better and the steeper angle of baffle cone (convergent section) had a stronger hit though a bit narrower band width.

Is it better to have the bleed tube/stinger protrude an inch or so inside the expansion chamber for better back pressure or better for it to just be welded flush for better pulse reflection. Just asking cause my stinger is all wrong and needs to be about 5/8id. 11in long Was gonna cut a weld a new pipe on. Not looking for torque as much as I am top end

 

[Street Ryderz]

Is it better to have the bleed tube/stinger protrude an inch or so inside the expansion chamber for better back pressure or better for it to just be welded flush for better pulse reflection. Just asking cause my stinger is all wrong and needs to be about 5/8id. 11in long Was gonna cut a weld a new pipe on. Not looking for torque as much as I am top end

If the stinger protrudes into the chamber it doesn't do much at an inch or so, if you put it all the way into the belly it reduces noise big time!
The back pressure is not really a thing with 2t's and a tuned pipe, your trying to get the reflected wave to over fill the cylinder over a desired band width so length from piston face to around 3/4 of the baffle/convergent cone is very important and then the stinger I.D. 40-50% of the exh port dia and more toward the small side for top end, I have lots of info here to help you figure this out.