While adjusting my valves on my 61, I found it difficult to get an accurate reading with my feeler gauge. The valve stems have formed an indent in the bottom of the rocker arms. I tried to adjust for .006 and .018, but was not confident that my reading were perfect. What kind of damage can I create by being out by a few thou?? Truck is running good, but I can here some clacking the faster I go. How worried should I be? Big blue.
I have kept a tool from the sixties called a P&G Valve gapper, that uses a dial indicator setup, and clips between the rocker and the valve spring retainer. This tool lets you set lash very accurately. Be glad to loan it to you, if interested. It only fits certain engines, but it probably fits your truck. Randy