On my SPAD Canard the egine is mounted at the back of the plane and uses a pusher prop. The fuel tank is in front of the main wing which keeps it about 12 inches in front of the engine. Fuel flow to the engine was erratic so I added a small 2 oz header tank close to the engine.

On my SPAD Flying Lawnmower the main fuel tank is mounted inside the wing and at 90 degrees to the fuselage and about 14 inches away from the engine. I use a 2 oz header tank near the engine to keep the engine happy. Never a fuel problem.

Fuel flow is as stated above.