You checked for a good spark at each cylinder? Use new NGK copper plugs 6BPES
if I remember right (You can check the search engine- enter "NGK").
You can look in the oil fill hole to verify that the cam is turning while cranking.

I like Randy's idea except 1: I'd put "Mystery Oil" in each cylinder and let it soak a day or more if you're not in a great hurry. That stuff really works to
free stuck rings.

2. You don't need a flood of oil in your exhaust, maybe wrecking the O2 sensor and/or cat converter....so
After the oil soak, get plenty of newspapers and crank the engine to blow
most of that stuff in the paper.

Good luck, Bill