Weber 32/36 DFEV Air Leak?

[Shadoobie]

So I just got a Spanish Weber 32/36 DFEV from Carl at Mirafiori and I'm having some trouble with it. The carb itself looks to be freshly rebuilt and in great shape, but I ran through every nook and cranny with carb cleaner and swapped the jets with some I know to be safe. Setting it at idle is a breeze, nothing unusual. However, as soon as I try to rev the engine around 1800rpm i hear a loud sucking noise and the car cuts out. Sometimes, if I hold the pedal to the floor, the secondary will carry it through to a higher rpm, but you can tell that the primary isn't doing anything. If I hold the choke closed over the at temp engine, though, it will lazily rev on the primary. I tore the carb completely down and cleaned out the Jets and everything else several times, but it doesn't seem to make any difference. I'm going to go ahead and strip it down again and soak it in chem dip overnight. Does anyone have any suggestions as to what else I should look at? -Josh