Which type of HD muffler. OEM take-off? Screaming Eagale (loud)?
OEM take off, a 150 should be a good starting point.
I agree with Dasch, what did you do to the white spacer. That controls about 1/8 throttle thru 3/4 throttle. That is normally most of your regular riding (well, except maybe Lancer and Sluggo's riding
).