Pushrod ?

You can check it assembled, set up a cylinder adjust lash, replace the valve springs with light checker springs. slowly rotate motor by hand until it is on the exhaust stroke. As the piston comes up stop every 5 degrees and push down on valve. Use feeler gauge to check piston to valve clearance. Turn it another 5 degrees and repeat until the piston reaches tdc and starts to go back down . Continue for 20-30 degrees atdc. There you go. If it wont turn your have your answer. You can check both valves but the exhaust is the concern.