Excuse me if I'm comming in here rather late...but we are talking about low flow velocity in the intake "manifold" area (after the carb ) correct?

After looking at a friends engine, it appears to me as though there is too much volume between the carb venturi and the crankcase?

The fuel/air mixture wets out along the walls of the conduit, instead of remaining in a fog or mist, and the resulting droplets cause flooding, or they put out the spark at low r.p.m. (because of this low flow velocity )

I have experience with Boss 302 and 351C 4V heads...and this is my 1st impression...FWIW

If such is the case, then it seems as though a re-design of the I. manifold is necessary.