Thank you Marty!

I removed the air cleaner and moved the throttle, could smell gas but didn't hear any squirting, so it might very well be an accelerator pump problem, like my mechanic was suspecting. Waiting for weber redline reply to my email.

I checked the vacuum ports. On the new weber,there are 2 ports: vacuum advance port and another one called manifold ported vacuum (vacuum retard). I have one connection going from the distributor to the vacuum advance port, but nothing plugs in the manifold ported vacuum.