Lou, the stock vacuum advance is adjustable by inserting a small allen wrench in the hose bib and turning left or rt to adjust with a vac gauge. Be sure the swinging weights in the distributor are free to move and not sticking. This can cause advance-creep and changing idle speed. Also note: modern cars these days routinely run at 220F and are not considered 'hot' until about 245F. If the car is not spitting up coolant, the engine is not too hot no matter what the gauge says. If you have a '71-72 car, the stock expanded- range temp gauge for '73-up contains its own calibrated resistor so as to better read true water temp. It reads to 260F. Mine needed no external resistor at all to read correct water temps.
To 'read' spark plugs, new plugs in any engine that's warmed up and put under load like climbing a hill, then cut clean without further idling or deceleration, is all that's necessary. This will not work in 1st. gear. A new engine will continue to loosen up and deliver a little more power/torque each time you run it. Most are 'broken in' and stabilize within about 250 miles. Then it's time to change the oil and get on it, IMHO!