This has been beat to death on here, put a timing light on it and go no more than 30 deg, any more and you risk breaking the crank.
yep, right on the nose. Many times, ive seen guys use the std 28 hub for the flywheel, only to have an offset coil, which already is advanced from the flat heads, and older 28 ohv.....turn up the timing without checking, and boom, broken crank.