Ticking noise

[Dougs 28]

Have a fairly loud ticking noise in the 28, so I did a compression test and all four cylinders are pretty consistent at around 70. So I changed the exhaust manifold gasket thinking it might be an exhaust leak on the # 4 exhaust port making the tick. Put it all back together and the ticking was still there, so I decided to take of the valve cover plate to see if a spring was broken. I do not know enough about this area of the motor to know what to look for, it appears that the distributor shaft has some rusty crud on it. Not sure if this could be where the tick is coming from. I have some pictures that I’m going to try to download. Just don’t know where to go from here….