Quote Originally Posted by doc_rock View Post
There's nothing under an updraft carb to stream fuel onto. It literally hangs out the bottom of the engine, with nothing below it. I think the scenario you describe is exactly why updraft carbs are used on aviation units in the first place - that and allegedly they don't flood the engine, but I've proved that theory wrong many times.

I would think that EFI (TBI) would be able to operate upside down since it is under pressure, and no need for a fuel bowl to sit and gravity to work it's course such as an updraft carb would have.
I would think the only concern would be making sure the IAC counts are at a minimum at idle so the air flows as strongly as possible through the throttle bores. Air cooled may get interesting. May have to use the oil as an engine temperature reference rather than the cylinder heads.