360 instal, going on 3 days, need help

Howdy neighbor, there should be no forcing involved. Are you having an issue with the input shaft going in the bearing? Did you use the clutch alignment tool? The engine usually goes in first, then level the transmission with a jack (or arms), and level the engine with the lift. Can you adjust the transmission fore and aft at the cross member? Try rocking it from underneath and swivel the transmission left and right while pushing. No need to put it in gear, out of gear etc.

Step away. Take a breath. Drink a beer.