What did I break?

Try shooting some oil in the cyl, if it still has 100psi the valves are ok, last one I had was at 15-20psi and the rest were 155-160.

Just to make sure throw a vac gauge on the manifold, if it's an intake valve the needle will be all over the place, the exhaust valve is easy to check with open manifolds/headers, it will make a loud pfft pfft pfft sound when you shut the engine off.