Carb to use?
You're combination looks real good. The cam is a little larger than we would normally use with a Speed Demon series carburetor, but you should be able to make it work. With a Stall speed as loose as you're using a Mechanical secondary carburetor should work extremely well. If you have hood clearance you may want to use a 4-hole carburetor spacer between the carb and intake manifold. It will increase the air velocity which will help with the drivability.