40 degrees initial!

AJ's on it, as usual.. idle is a no-load situation and you can advance the timing more than is desirable for driving. Put it in gear though, and ugh. The 20 you had sounds good, if it idles strong and clean there. Idle timing just needs to be 'enough' and the carb settings take it from there. A problem would be, if you needed 40 degrees just to get it to run right.