[Gaz64]

You need a timing light connected to any engine if the timing has been altered in any way prior to fire up.

I have seen a few cars started without a timing light, some with near drastic results.

So you need the light connected, and as soon as the engine is restarted, get the off cold timing down to 15 or so, then warm the engine up, and set idle timing at 12 or so.
I prefer a digital dialback light, so you can check timing at any rpm, including tracking the advance curve.

Gary