what is the right distributor contack point gap clearance for the nissan Z20s 4 sparkplug, carburator type.

think like a match book cover. will work ... bump motor over til the lobe on cam is high and points open stick match book cover in gap and tighten

Use a dwell meter it is much more accurate.
60 degrees on a four cylinder

.016'' and dwell angle running of 45 to 52 degrees. Always reset the spark timing to the deep slot and yellow line onthe crank pulley. 2 degrees of dwell can equal 4 degrees of crank timing change. You still running one of those old timers did you ask the valve lash a couple of days ago? ________WARNING old fuel system plastic cannot stand up to 10 to 15% ethanol that is in the gasoline these days carry a fire extinguisher.