Loosen the bolt holding the distributor in place, and turn the distributor counter clockwise. If it bucks the starter, it is too far advanced.
counter clockwise.
Turn it clockwise to retard it. Counter clockwise to advance it. If this was not your question then asked it again.
cam timing will not change ignition timing i would try 8 or 10 degees advance at idle with the vacuum advance disconnected.
On the front of the timing chain cover, drivers side towards the top of the harmonic balancer.
6 or 8 drgee
There is no timing belt on a 305 unless it is an aftermarket belt drive system.
The vacuum canister can advance 24 degrees beyond initial timing.
counter clockwise
Timing Advance not working or fuel sensor messed up.
Top Dead Center
6 degrees BTC
same as a 350