Big blocks love their timing in early. And ones with larger cams like a lot of initial. But most guys that don't have a lot of cam will not be able to start their car when hot with the advance locked out.
Personally, I set the initial just below the point that it kicks back against the starter when hot. It varies with different combos, but somewhere in the high teens to low 20*s usually gets it. Then bring the timing in as fast as the engine will take it and not knock under load in high gear when hot. The taller the gear, the slower it will need to be brought in. But, all-in by 2,500RPM is ball park.
As an example, my last 499 w/250* cam and 3.91s had 25* initial and was all-in at 1,800RPM. I tried it locked out, but it was almost impossible to start hot. Although, I had a security switch on the ignition under the dash and I could leave the switch off until I started cranking it and then it would usually start when switched on. It was just easier to drop the initial back and put the advance back in.
