If the carbie was left on, there will still be a small amount of vaccuum available form the idle oriface. It's debatable that any fuel would be able to find it's way through there to sustain the engine at idle. But if you say you done it, maybe it does.

ive done it too using an su carby and one su carby machined down into a throttle body

Sikdatto1200 do u have photo(s) of that setup?

unfortunatelly no, what i did was get onto it with a grinder and then lathe it down so there was approx 10mm after butterfly left. Id suggest finding a smaller throttle body off something and using that, much easier. Was using a ct12 from twin 2j setup, no carbon seal. Ran the su carby in front of the turbo real close, then blew into the throttle body. Worked fine cant comment on longlivetity as converted to delco efi from a camira but cant see a prob as no vaccuum to suck oil on intake of turbo. As far as im aware the carbon seal only prevents oil being sucked out under vacuum, the fuel going through it shouldnt leak in. Make sure you dont get fuel puddling or it will go rich as soon as you crack throttle after ideling. Got the idea off a mate from his turbo mini setup and it lasted ages before he got sick of box problems