Excluding RA engines, Pontiac did not use adjustable valves. Index marks on the cam and crank sprockets should be facing each other..crank index up...cam index down. If everything is in "time" and you have spark, fuel, and compression you should have something..pop..fart or fireball through the carb, or a engine that runs....something.
Have you replaced the wire to the distributor? The original wire I believe was a resistor type...which would lead to a weak spark.
Have you checked your compression???
Dito what Bob S. said