I had a '65 Rambler with a 196 ( solid lifter engine ) that had 1 sticky valve. stuck open once long enough that when the preassure was let off the pushrod, the pushrod slipped out from under the rocker and caused a dead cylinder.. soloution was to put it back togther, adjust the valves and hold preassure on the rocker with my finger while it was running, until it freed up... this should work for you too but it really should get taken care of.. in my case, it was a daily driver, that was ( at the time ) arleady laid up too long.