Exhaust valves stuck in head

I have a 1978 440 from a motorhome with 452 heads. I was tearing down the heads to put in new valve seals and clean everything up. I got all the intake valves out fine. However, the exhaust valves won't come out further than the grooves where the locks are. It's like the grooves are catching in the valve guide as soon as they get there.

Any ideas?
Author: admin