R3W7 Assembly

Fuel closer to valve is good for part throttle and transients and idle quality (metering is always better).

Fuel farther from the valve increases torque and hp at higher revs because it's cooling the intake charge as the fuel evaporates, but the metering can be less than ideal due to wet flow, wet walls, etc.

The optimum placement depends on the application. A dedicated drag car that never sees under 4k should (theoretically) have the fuel way up the runner. The more it's driven on the street, the closer to the valve it should be.

This of course ignores whether the intake tract is decent or not. If it's a twisty-turvy flow path with a tight radius port then obviously the net effect will be different.