Just a guess but the symptoms of too retarded timing are quick start up, good idle, sluggishness and possibly backfire. OR, if it runs better when warm, this might suggest a vacuum leak.
Perhaps you should a) check the timing specs and then if they are okay b) put a vacuum gauge on the engine and see how the gauge behaves. If you get low vacuum or a very eratic needle, you might use carb cleaner to check for vacuum leaks and also do a compression test.
Last but not least, re-check all your tune up parts, especially cap and rotor and plug wires.