If all stock and timing,plugs, valve lash bla bla bla then my experience suggest 2.5 turns for very good economy and 3.5 for balanced economy/power.
Use this info to be sure that your valve lash setting is done right, don't overlook this setting cos it's a bit tricky, if you've done it good you will get good idle.if very good then very good idle ...... and slightly faster and smoother idle.
Good luck with excellent setting and idle and without vacuum leaks!