RE: Stihl 046 conversion
Looks great!!
That manifold is very similar to the one I made for my 62cc Stihl. But I am afraid you are going to find you need more heat insulation for the carb. That's what happened to me in testing mine....
The Stihls are like the Zenoahs; they really like to rev, so you might resist the very common urge to overprop it. Let it rev and you'll love it!
AV8TOR