The flash of your timing light lets you know where your #1 is firing in relation to the crankshaft position. If it will line up on the BB your ok even if not in the exact factory location. You can drop the distributer in in any location and move the wires so #1 is over the rotor with the #1 piston in the firing position, of course when the next guy works on it he'll cuss you out. The engine will always sound better if advanced a little from the factory spec but can detonate or lose torque if done to any extreme. What we do on one that is overly lazy like you describe yours is run it till it's at it's running temp, then advance in increments till it pings when you accelerate in high gear at about 20 mph, then back off a couple degrees. Now kill it and start several times to make sure it doesn't "kick back" at the starter. This is a much more common situation on engines with timing chains that become stretched than it is on a gear driven setup like yours.