I checked the outlet hole, and it is completely clear.

As for cutting the header. I didn't. All I did was cut 1 1/2" off the back, and then JB welded it, into the moosecan. All I did was just cut the header, then put that piece in the moosecan. So really I didn't shorten it.

On the 6 1/2" by 1 3/4" can. I would have to completely shut the high speed needle vavle to get it to lean out. (Bad) I though Dave McD was getting about 2K more than I was so I just swapped cans, to the 6 1/2 by 1 1/2 can, and that is when My motor ran good. But is was only at 12,000.