UPDATE: The good- I got the engine fired up again today after setting the valve clearances, soaking the cylinders in MMO (compression improved markedly because the engine got a lot harder to turn by hand), cleaning the oil passage under the lifter cover, installing a '59+ rocker oil connector. It fired up and seemed to run/rev a bit smoother. There is oil pressure to the rockers as evidenced by oil seeping out through the top weep holes in the rockers. The rear ones seemed to be leaking out a bit more than the front ones. However, they all appeared to be getting oiled.
The bad- the car still smokes quite a bit, especially as it gets warmer. I had a look in the cylinders when putting some MMO in there and the tops of the pistons look very sooty. There is some smoke coming from the crankcase ventilation tube, which leads me to believe I have some blow-by, but I don't know enough about these engines to say that it is certain (let me know what you all think).
I'd appreciate any input on next steps. My initial thoughts are to do a leak down test to see how the rings/valves may be sealing or possibly get a head gasekt and pull the head to have a better look at the cylinder walls, pistons, and valve seating surfaces.
Is the smoke blue or black?
Blue burning oil.
Black engine is running too rich.
If your engine sat that long without running chances are the carb is messed up and needs to be rebuilt. Then a full tune up on the engine.
Also if Marvel Mystery helped the rings that much that you saw a difference then that engine would benefit from running a lot more to help free things up some more. The oil needs a chance to work in to everywhere and get things cleaned and freed up to all they can be.
Do not underestimate the need for new oil to work its way through an engine.
My son's truck had two badly bent pushrods and valves badly out of adjustment. Getting new pushrods in and an initial cold valve adjustment reducing the valve lash to .005" over the maximum made the engine run a lot quieter.
Then putting in a new oil filter and changing the oil made the engine even quieter.
