318 diagnosis

Hang on, don't take anything apart yet!
IMO
#1 this is not a valve seal issue , and
#2 highly unlikely to be a valley leak into the intake ,and
#3 not a ring seal issue either, nor a an oil-ring.
#4 IDK yet what the problem is, but I suspect the PCV. I'll bet you have it plumbed to one of the intake runners.
Here's the test;
Pull it out of the valve cover and just flip it off to the side. Then fire it up and keep it at a fast idle to clear the oil out of the intake; Then repeat your test as in the first video.
Meanwhile, see what's coming out of the open hole in the VC. If, at idle, you have a stream of blue smoke coming out of the CC, your rings are not sealing. If you have a puff once every revolution, you have a vertical gouge in a cylinder wall. This will not show up on a regular LD test, but the cylinder pressure in that hole will be a lot less than in any other.
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Now, as to the PCV valve, there is a designated port on nearly every street-carb I have ever seen, which is where you plumb your PCV to. It is almost always on the front between the throttle-bores and enters the carb underneath the throttle blades. If yours is NOT there, make it so.
Do NOT plumb it to an intake runner.
Do not plumb it to the Secondary side.
If you have to; you can drill and tap the intake plenum, for a hose-barb, in such a way that it connects to all the runners.
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Speaking of your compression test results; a pressure variation of from 129 to 140, with just 1100 miles on the clock, is giving me the hebejeebies; that's terrible. Yeah, I know what the sevice manual says, but old AJ here, says that whatever hole scored 129, it has a problem.
Throw out the highest and the lowest numbers, then average out the remaining six, which will then be your mean target. Say you had the loser at 129 and the winner at 140, and all the rest averaged out to 138. Badaboom, that loser is ~7% low, and it is sucking down your average power ALL the time.
Find out why.
But if all the rest average to 132, then your loser hole is only 2% low, and you gotta wonder about the 140psi hero.

Because you have doctored your valve gear in an unconventional way, here is what I would do;
I would remove all the valve gear from the smoking side, then do a Leakdown at 80psi on those 4 holes. When you pressurize those cylinders, the pistons will fly to the bottom of the bores, where the holes are the roundest and, the least worn. So then, your results should be as good as identical in each of those four holes unless the valves are leaking.
If you get a troublesome hole, with the piston now at the bottom, you can bop the valves a few times, and see if the pressure changes. If the pressure comes up or changes at all, then the valves are Not sealing properly ........ and you have a decision to make.
But if the pressures vary less than a few percent, go to step two; which is,
Reset your LD tester to 20 psi, and pressurize a hole. Then take your longest breaker bar and turn the crank over, CW in normal rotation, stopping every 20 degrees or so, to let the LD tester stabilize. Obviously, if the cylinder walls are ok, then the LD reading should Not change from bottom to top. If suddenly the pressure goes away, then most likely, you have a gouge in the cylinder wall. Test all four .
Caution, when you get to the top, your 3.91 bore at 20 psi can generate 240 footpounds of force. your breaker bar might be 18" long max which means the instant that the crank passes TDC, it is able to unleash 160ftlbs of force into your bar. Do NOT let that happen! Have a helper ready to dump the pressure at your command; Do Not try to do this alone; I am not gonna reimburse you for hospital bills, lost wages, broken parts, etcetera. This is the only test I know of that can find a gouge.
I'm not saying you have a gouge in your cylinder wall. Really, I'm leaning towards the PCV valve. But like I said on line #4 above, IDK..... yet

BTW, when I do a compression test, I crank thru as many compression cycles as it takes, to get two successive, about the same, psi numbers; AND, I record the number of cycles.
If I see all the numbers approximately the same (which would be ideal), but 7 holes pumped it in 4 cycles while one took 9, then, even tho the numbers indicate really well, there is in fact, a problem in that 9-cycle hole.