Mine came with the backplate already drilled and tapped, and a pressure nipple furnished, so no big deal. It is simply a problem of too little muffler pressure with a two-stinger pitts style muffler. The Perry pump solved the problem as it does with my Webra 120s (2) and several others. The Cline would be just as good also.

Mine also has very low compression, which would seem to me to reduce the ability to suck fuel somewhat. But it runs strong in the air, and that is all that matters!