La318 cylinder head question

Ok, so I’ve pulled the valve cover and rocker shaft. No sign of broken spring, valve seems to move fine when using pry bar to lever it down. Obvious marks on piston from valve contact. I don’t get it. Stuck lifter maybe?

I assume I’m going to have to pull the head to inspect the valve for damage, so my next question is, how the hell do you get the head off a 318 in a 1966 Dart? I can’t get the exhaust manifolds out of the way enough to get the bottom bolts, especially on the drivers side, and I can’t get to both flange bolts at the bottom of the exhaust manifold in order to remove it entirely. Is there a trick or tool I’m missing? I’d really rather not pull the whole engine again just to remove the heads, ya know?