That chain is SHOT; 3inches one way AND 1.5 the other, if that's what you mean, is a wonder it runs at all.
But even if the total is only 3, that is still a wonder.
However, your test is IMO invalid as to testing chain slack, because it includes too many variables. Your method allows the slack in the oil-pump drive to befuddle the measurement, as well as any shaft endplay, as it rises and falls with each the reversal of the crank.
The proper way to do it, has nothing whatever to do with the rotor. Just rotate the crank in a CW direction until it hits resistance. Now, reverse directions, and slowly slowly back it up until you again meet the slightest resistance; Then repeat the test several times until you get confident about feeling the threshold of resistance. Now estimate the number of degrees between resistances.
Here's what's happening;
the valve springs are forcing the cam into a sort of stationary position, thru the pushrods and lifters and specifically when a lobe , any lobe, meets a lifter and trys to lift it. Once there, and you stop, then it doesn't want to move anymore; on account of the Scientific Law that states, that:
an object at rest tends to stay at rest.
But the drag of the piston rings, in comparison, is waaaay less. So with a lil practice, you can easily find this position, after all; there are 16 lobes so you're bound to find one right quick.
What you want to see is ZERO "lash". but I think I have seen an acceptable number is 3 degrees. Engines have been running for decades with more than 3*, so it's not a panic. But if you get to more than 5* it is starting to affect your timings, and if you have a nylon coated camgear, you are starting to push your luck. If you have a double roller, it will run another 50,000 miles so don't sweat it. If I had 5* slack, I would replace the timing set because, 5* retards BOTH your cam timing AND your ignition timing. The latter you can compensate for, but that 5* has moved your power-peak up about 200rpm, and taken about half that off the bottom, making it sluggish twice; once for the cam-retard, and again for the ignition retard.
But it get worse; the retarded cam has dropped your cylinder pressure, making your bottom end weaker; and the retarded ignition timing, means that the Peak Power is also reduced. So now, the engine is making less pressure on the compression stroke and then lighting it off later ,as the piston is running away from whatever pressure the expanding gasses can muster.It has lost low-rpm power, and lost high-rpm power and power every where in between; not to mention the lousy fuel-economy she-s getting.
IMO, 5* is totally unacceptable.
