Advancing timing if running constantly @ 4,000 + RPM's

Should I advance my timing if I'm running 4,000 + RPM's constantly... or should I turn it to the base timing... or should I retard the timing a bit?

Side Note:
@ WOT the manifold vaccum drops to "0" so the vaccum diaphragm advance is not operational.
Release the gas pedal... vaccum rises, fuel increases because the pressure difference between the barrels and the float bowl.
and vaccum advance is once again operational.

Timing:
It doesn't make sense for me to start the spark early if I know that the valve are staying open for such a long time...
280 duration Intake
288 duration Exhaust.

If I fire too early I end up with no power since it will bleed out the valves before they are fully closed and put resistance on the upstroke of the piston.

so setting Base timing makes sense since I know the piston will be aproaching or at TDC and the valves will both be closed.

But then again since the time the valves stay closed is also shortened I should start the spark early. because even if the spark is @ TDC the flame itself still needs time to burn and I will end up fireing on the downstroke...


Please correct me if I'm wrong about anything I just said...

I did find as others have found before me, that advancing the timing (On N/A Cars) a bit increases bottom end... so is it safe to assume that as it increases bottom end, it decreases top end?


I tipped out @ 7,700 yesterday morning and blew a seal on the float needle valve. :eek: Good O'l 92 Octane was leaking from the top-Hat gasket onto the manifold. :flamer: