Hello everyone! This is my first post and couldn't be more excited to be a part of this community.

I have been searching endlessly on the internet for a solution and am just looking for some additional input.

I recently purchased a 1951 300 in remarkably good, original condition from the 2nd owner. It must have sat for a while because it sounds like one of the lifters is sticking. I am coming to that conclusion from the very loud ticking/tapping sound that matches engine RPMs. From touching the spark plugs and feeling the tick, to having a long screwdriver as a makeshift stethoscope, I have narrowed it down to the 2nd or 3rd cylinder. I've only owned it for 2 weeks so I haven't been able to get to far into it yet. Here is what I've done so far:

1. I put some Marvel Mystery Oil in (the oil in the car is in very good shape and looks like it has less than 1,000 miles on it) and I have driven it about 300 or so miles with the MMO in.
2. I removed the front side valve cover and watched the springs/lifters with the car running. I couldn't tell from the angle (standing looking into the engine bay) which valve isn't operating correctly. Due to time constraints I wasn't able to take the passenger side wheel and inner fenderwell off prior to viewing.

I have ordered new valve cover gaskets since the existing one basically fell apart when I removed the cover. I plan on taking the wheel off and inner fenderwell off and seeing if I can look up at a better angle to see which valve isn't operating properly.

Does anyone have any additional input on this? It's very annoying, but more than that I don't want to damage any of the valvetrain by driving it. I have everything to do a full oil change after this is complete as well as most of the other fluids.

I appreciate your help!
Chris (rockabilly)