Pay attention to the little asterisk. See where it says the distributor rotates clockwise? You know why? Because the 307 was not a Pontiac engine. It was an Oldsmobile engine sold in Pontiacs. Pontiac never made a 307.
That`s the only reason I was asking just incase the op was placing the firing order in the wrong rotation and cause havoc. Just trying to help the OP. I`ve read chev based engine.
Anywho , strange it ran great before he did all that work, seems timing related to me.
Good luck OP
