The only thing mechanical that would affect your ability to dial in ignition, is the timing belt. If you are positive that the belt is installed and tensioned correctly, I would look to the distributor itself, specifically the TDC sensor.

Just to be certain, are you using the correct mark on the crankshaft? They should look just like this on the crankshaft:


-- TDC

-- 14 BTDC
-- 16 BTDC
-- 18 BTDC