brass would be heavy, but would work. it doesn't have to be the same length, I think what I have is HDPE, which should work fine...

external pulse is just drilling and taping in a fitting, just somewhere in the crankcase where it doesn't interfere with anything, you also need a carb with external pulse, or just work the pulse hole into your carb adapter, that's half the reason I'm thinking of making a standoff/bracket for the stock setup, plus in theory it should be lighter than a big chunk of aluminum... I don't know, 6 of one, half a dozen of the other...