I just built a 340 with 9.4 SCR and a 220 @ .050"camshaft, that was set at 22 initial and could have had a tad more. If it doesn't ping or start hard when hot, it isn't too much. Drag guys lock out their advance most of the time, because the engine makes the best power when at it's optimum timing number, and they are usually running enough cam to bleed off some of the cylinder pressure that causes hard starting anyway.
