Went and bought a new coil and it still just cranks over...

 

Are you getting a spark? Check base timing is correct.

Repeat throttle body starting fluid startup for temporary start.

good luck

 

I would make sure the battery is fully charged and pull the spark plugs and see if they are fuel fouled and if so replace them rather than clean them. Occasionally you get a vehicle that cranks at normal speed but battery isn't charged enough to get proper ignition. I would also check the main ground mentioned by another forum member considering you changed the engine.