Short of pulling the valve covers, a vacuum gauge will indicate if you have a broken valve spring.  Beyond that, it’s time for some basic trouble shooting and possibly a thorough tune up which will include setting the valves.  A vacuum gauge and performing a compression test on the engine will rule out a majority of the mechanical problems that could be taking place.

Lorena, Texas (South of Waco)

If the plug wires are routed correctly and / or do not contact any parts of the engine and they still melted, then something is getting very hot and usually that happens when it is lean.  Lots of stuff can go wrong when an engine is lean.  Make sure you have it tuned correctly.  Do you know how to tune the carburetor and distributor?



Lawrenceville, GA

This started awhile back, noticed plug wires being burnt in a few spots. replaced them still have the issue.  Pulled carb a BG JR.. I thought I had it tuned right with a blow proof power valve.  With a 57+ distributor.  New plugs, new wires. So now I don't know if I got a broken valve spring or the dist is going to crap.  Used to run well with the original fordomatic dist and coke bottle carb.  Now it seems to be snowballing to not being driven.