I would agree with Joe H: Sticky valve guide is common with new rebuild and almost certain when they get hot. Not a lot of lubrication at the guide on a good day. New guide and new valve should have had a lot of assembly lube all over it when it was installed. That would have been cleaned off real soon after starting up. Intake would be washed off from fresh air fuel mix coming in and exhaust would have been burned off just as fast. If the valve will move now you may have no real issues just keep it cool while running it. Look at the lifter as has been suggested If it is good then find a push rod and see what happens.If the valve hangs up when you push on it then you need to get it fixed. But if it moves you may be OK.
