This concerns my 67 230s (180.947). About halfway on a 15 mile trip, a valve noise developed. It is a clear tick that can be distinguished as one valve possibly stuck open. I would like to try and free the valve. Does any one have any suggestions before I go out and beat it with a leather mallet? I am going to assume carbon particles are causing the blockage. I have also heard that dumping diesel into the carbs with the engine running will burn with a higher temp and possibly removing the excess carbon.

Have you tried using mechanic's stethoscope to figure out exactly which valve is sticking? You must have already checked valve clearances. Worst case scenario could be bent valve stem..... cant say I've ever seen this problem - but have seen some helaciously worn out valve guides. Am not sure if those were self-rotating valves or not in '67.... but that's another thing you'd probably want to know to diagnose the trouble. Hell, also look for cracked or broken valve spring...... thats something which uncommonly although occasionally can occur.

If it was me, first thing I'd do is pull the valve cover and check clearances.... then pull the sparkplugs and rotate the crankshaft while checking valve springs and rocker arm action for anything weird. Am kinda thinkin cracked valve spring on account of the problem suddenly occuring.