Re: Timing on a big block
On a warm engine, disonnect and plug the vacuum advance, then set the idle to about 7-900,..whatever she likes.
Then set the initial timing to about 10 degrees as stated above,..recoonect the vacuum advance, then drive her. If she doesn't knock or rattle (most noticable when you stomp on her at lower rpm), then bump to 12, etc.
When you find the detonation point,..or pre-ignition, then back her back down a bit, and lock down the dist.
Fyi,..my cars all like around 15 degrees (+/-),..I run 93 octane.