Any expert diesel advice?

[Smokestack lightning]

I had been parking my 81 Diesel Pup on a small incline of a few degrees and when I pulled the dipstick out it had a small amount of oil on the end, I foolishly had not parked on a completely flat surface and checked it after 15 minutes of being off. I had a new oil leak at my dipstick tube that I did not catch. I was on the highway and noticed power loss and ticking so I pulled over and added oil. These engines are so tough I had ran it real low once before when the oil line to the alternator had a leak, it was fine after adding oil. But this time it kept ticking but ran pretty good besides that. I tried to limp it home on side roads and it quit. I got a tow truck and had it brought home. It will start but seems to be missing and it's running rough and not smooth. I pulled the push rods to see if they look bent, they seem fine.
Does anyone have an idea of what it most likely is that I did?
I am hoping it is nothing too serious where I can just put a head gasket on or something. I will re-install and torque the rocker arm shaft, adjust the valves again and check compression.
Oh yeah, I had checked the valve lash and strangely one cylinder would have a bit too much gap from the 0.016 in. gap and another would be a bit too close of tolerance. I am great at adjusting valves and I had the valve lash real good and even.
Any advice would be appreciated. Gary

[Halden]

First off, how much oil did you need to add? Oil pressure light come on?
Push rods don't just randomly bend... I doubt a head gasket is the issue.
Any chance you've overheated it?

[trooper T/diesel]

Best case is, it needs injectors.
Worst case is, oil starvation.
With oil fill cap off running, excess blow by?

[Rodzbuck]

Ticking and too much gap. I would say burnt valve, bent valve stem, debris or excessive carbon broke free and is now stuck on the valve seat. I agree with Halden, any chance you over heated it. Your on the right track, do a compression check and if you have a cylinder off you might want to pull the head for a more closer inspection