[nkaminar]

Do this: Use the manual throttle on the steering wheel column to set the engine rpm to a fast idle. Now move the spark lever up until the engine rpm just falls off a bit. Now move it down one click. That spark lever position or one click up is where you should be driving. See if you click goes away and performance is improved.

This position is called the knee in the spark ignition curve. It is where advancing the ignition will not improve performance but retarding the ignition will hurt. The knee actually is different for different driving conditions. A little more retarded for heavy loads at low rpm and a little more advanced for light loads at high rpm. Experiment and remember where the lever is set under different driving conditions.

Now, if that does not solve your problems, adjust the valves. The tappet clearance will be different for different cams but a good starting point is 0.012 inch for all valves.

If the ticking goes away under load or idling, you may have loose rod bearings. If that is the case then you will have to pull the pan to measure and adjust the bearings as needed.

It is normal for a Model A engine to have more engine noises than a modern engine. Have another Model A owner listen to your engine. It can also be a worn cam gear or any number of other things.

One idea is to record the sound using your iPhone and then play it back at 1/4 speed. Gear noises clearly sound like gears at low playback speed. You can also publish the recording and have a link to it so that people on the Barn can listen.