A couple of things came to mind about that vintage. The power feed plug was of the "bad" variety, especially if the back side is flat (no finger grip).
Some of the "68 Automag" regulators were not lined up with the valve port at 12 o'clock. This caused noticeable shootdown, but can be corrected with a new port drilled at 12 on the reg.
Some of these also had regulator piston relief settings that were set a little too low for the level 10 bolt, but it seems fairly random, especially if you set the velocity lower and with a gold spring.
Springs about 1/4" to 3/8" over the bolt tip are good. The early level 7 bolts had foamies, then they started playing with the foamy-less bolts.
Of all that, the feed plug was the most annoying for me.
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