Bill:
At the risk of sounding stupid, is it feasible to rotate the carb 180degrees?
There is a pulse port on the engine side of the carb that
must align with a hole in the case/head. you may be able to rout out a channel on carb side of carb adapter (the spacer) or make a 'twister' adapter plate and do the routering on it. Or drill & (tap) for a nipple into the case and use a fuel line nipple in the cover plate on the side of carb with center screw. You will probably find a raised ring of metal on it and that is what it is for.
Check out the Engine Conversion forum. A number of knowledgeable posters there as well.