Fo reference, I believe he bypass valve opens when there is a 10psi difference between input and output? Not "clogged", but "restricted".
Other than the oil filter element inspection, when you drain the oil, you can put a magnet in it to catch what comes out AND filter it through a drip coffee maker filter. But be cognizant of the residual oil in the low parts of the oil pan.
Other than pulling the motor, you can remove the oil pan, intake manifold, valve covers, with several drain pans, and wash the innards of the engine with Varsol to your satisfaction. Clean things up, afterward.
With the oil pan off, you can also remove a main cap or two, plus a rod cap or so, to look at the bearings and crank journals. Theory is that the bearings are soft enough to allow foreign material to embed in them first rather than score the journals (which are harder)?
Then, after all of this, put the metal back on the motor, a new oil filter, fresh oil, then remove the distributor and operate the oil pump to further flush the system of debris. Another oil change with a new filter. Then reinstall the distributor and make it run again. WITH a magnetic drain plug and a magnet on the bottom of the oil filter too . . . long term.
One other thing you could do is get an oil sample and send it for testing to look for "wear metals" which are in the oil now. Then after any clean-up activities and the next oil change after that. This might be one of the first things to do, then see how that testing goes and determine what needs to be done afterward.
Good that your supplier is sending some new parts!
CBODY67