200x Supertrapp exhaust owners: Tip to get more performance

[rg97]

I'm working on my 200x powroll replica and the supertrapp needed some new paint. So I go and blast it, and I look down the head pipe (head end), and There is some weld about 1/2" into the pipe that constricts the pipe anywhere from 1/4" to about 3/8", where supertrapp welded the head piece to the main header. It constricts the pipe at least 30%, and I'm kicking myself for not taking any pictures when it was like that, because of what I did next. It is possible to take the sloppy weld down without sacrificing the strength of the head pipe.
I took my die grinder with a 1/2" carbide cutter and took out the weld until there was about 1/16" to 1/8" weld left all the way around, then I took a sand wheel and smoothed the rest of it out so everything flows freely and smoothly. If you have a supertrapp I strongly recommend doing this as well. Based on what I see, you'll get about a 10-20% power gain, if not more. On ported engines and high HP machines the gains are even better.
Thought I would share!
I will try and get some finished pictures later, along with the tools used pics
Tools used list:

Air powered Sioux Die grinder @ 20,000 RPM with wrenches for changing bits
1/4" Carbide cutter (use 2nd)
1/2" Carbide cutter (start here for major hogging out)
1/4"-1/2" Sand wheel (80-180 grit will work) (use 3rd)
Vise to hold pipe in place

[Dirtcrasher]

75% of all Super Trapps' refuse to come apart or are destroyed in the process. Tip #2, if the prick does come apart, use copper never seize on all mating parts after smoothing it all down.