In almost all cases, the engine will make more power when the injectors are higher up but there are some trade-offs. Additional area of wetted manifold will increase the magnitude of AFR transients upon throttle angle change.
This can be counteracted by proper accel enrichment and decel enleanment.
End-of-Injection timing parameter will have greater effect on power with the injectors further from the valve, especially with duty cycles below 50%. Any standoff created by the high mount injectors must not be allowed to condense and puddle in the air cleaner or air box assembly or the risk of fire increases dramatically.
longer distance down runners and more time to mix with the air... shooting injectors on the back of the intake valve is done for emissions more than HP. alot of cars have this done... or they have two sets of injectors... one for low speed up by the valves and one for high engine speeds out on the TB's..
