Another thing to consider is if they are using an early cam (with an adapter for the distributor drive bolted onto it - which is what I see), then they probably do NOT have the oiling provision that Ford added to pass oil from the front cam journal to the front of the snout of the cam. This did not exist from 32 - 48 and it is very important when running the later timing gears and the side-mount distributor timing cover.
Unless they drilled the cam journal and center drilled the cam shout (highly unlikely), then this is most likely your problem. Without pressurized oil to this front thrust surface, you have direct metal on metal contact - so you'll soon have the very issue you speak of. This is also the reason that Ford switched the timing gear teeth angle - they wanted the cam to touch the front cover and ride against it. This is a mistake on the builder's part . . . plain and simple.
Why - Thrust Direction Change: 1) It helps keep the distributor timing more consistent (cam touching the front all the time) - as when you allow the cam to walk, the timing advance will move as you let on-off the throttle (only takes a little movement to cause over 5 degrees of timing fluctuation. I prefer to setup the backlash/thrust to be as tight as possible - like .003-.004 - to limit any timing movements.
Fix: Outside the potential issue of the bolts hitting the cover, if you want to continue to run the early cam, then it needs to be correctly drilled and the front adapter needs to have a hole all the way through it (if it does not). Also, the forward thrust dimension needs to be as close to .004 as possible (with the gasket in). Beware, sometimes the wrong gasket thicknesses are used. Depending on the thrust, sometimes I remove the gasket and use RTV. Also, I've had to "tune" the flange thickness on certain cams before. Many ways to skin the cat - but the thrust dimension is important.
Note: The aluminum cover is a bit more forgiving (as it relates to the amount of oil) - but it should not be an issue either way (with correct oiling).
Here is the oiling hole on a 49-53 cam:
49-53Oiling.jpg