Sami says,
     
     >>     I *DIDN'T* check the condition of my valves on my '77 dual port 
     >>     and it dropped a valve head on number 3 when I was 250 miles   
     >>     from home. The
     >>     engine ran perfectly though for the 8 months up to this point. 
     >>     Don't want to scare you but I would thoroughly check the engine 
     >>     if you're going on a long trip.
     >
     >How do you check for valve fatigue without taking the thing apart? I 
     >know a repeatedly tight valve is a sign, but what else?  TIA!
     
     I guess there's no easy way. You could pull the heater boxes so that 
     you can seen the valve stems down the exhaust ports - I don't think 
     inlet valves ever break, do they? But while your doing that you may as 
     well pull the heads if they've never been rebuilt, valves are very 
     cheap!
     
     Lee.