RE: Converted Y/A F-16A to from DF to pusher
I have no experience with the set-up you describe or with the engine you will use, but my research in this forum leads me to believe you would need a pump. Even if the engine can provide enough of a vacuum to draw the fuel from several feet away it could still be flooded in an extended climb or lean out during a long dive. Read what guys have to say in the posts about the combat models F-16N (similar set-up to what you are describing). They ALL recommend using a pump or getting a pumped engine because the fuel tanks are so far away. As far as F/A-18s go, I know a lot of people have had success with the G&P F/A-18 without a pump, but the tank is mounted far aft and a pump really isn't required. Good luck; let us know how it turns out.
Tim