1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
Rick (rbyrne) is right on the money here. Those old points clocks were not very accurate. Like any old clock they have wear areas on the shafts which also get dry and the points get worn too. A quality rebuild will help it a lot. If you need a reliable clock the quartz kit is the way to go. An NCRS judge will look at your clock to see if it is moving steady or jerking like a quartz though. Ot's a small deduction.
OK, this is not too difficult, but it requires some patience. If you have an owners manual, it tells you how to do it there.
Basically, when you reset the time ahead (cause it was slow), there is a mechanism inside that speeds the clock up (tightens up on the balance spring). When the clock runs too fast and you have to set it back, the reverse happens.
You have to move the time in the direction you want in small increments (2-3 minutes at a time), and then see how it works. I now have mine set where I only have to re-adjust the time every few weeks. Used to be every day. Took a lot of time to get to that point.