If the dots are not infact lined up the cam will move approx 20deg for each tooth it is out.
a non stock cam will need a non stock timing curve. usually a lot more initial idle timing.
if it was the 350-290HP GM crate motor it has a high perf cam and will like a moderate increase in idle timing
18 to 24deg at idle is typical.
measure the cam lobe lift. a wiped cam lobe is a possibility watch the rocker motion as the engine turns.