You can try an impact wrench if there's space for it.
There's a hole at the bottom forward edge of the bell housing for access to the bolts that hold the torque converter to the flex plate. I'm not sure if the transmission mounting plate is strong enough to support wedging a screwdriver against the ring gear.
If you can rotate the engine, pull off the valve cover and check each valve stem when the cam is not 'lifting' it. There should be little to no clearance between the cam and the valve stem. Maybe absolutely no clearance. If a valve is bent, it will likely not close all the way so you'll find a valve stem that sits lower than the others when the lobe is not on it.