[Rick Parker]

WOW I've been chcking on this for a few days and my head hurts. Remember Physics 101........"Liquid seeks its own level" I think the dimension you want to fine tune would be the static level of the fuel in the main well (jet assembly removed) and the bottom of the well where the main jet seals in its tapered counter bore. This will in turn mean the standing level of the fuel is uniform and the various holes on the emulsion tubes are uniformly exposed and ready for action. Any fluctuation in this dimension between carbs regardless of origion will cause irregularities in A/F ratios throughout the RPM range as well as poor transition and stumbling. If the dimension of the transfer tube to the jet seat is different between the Italian castings and those from Spain I do not think it can be "Tuned Out" and you will constantly have transition timing differences. JMO