<VV> Varying Compression Readings?

[GYoungwolf at aol.com]

I was checking compression on a '64 110 engine today, when I noticed that I 
can "pump up" the readings. Am wondering what that means? I was using a 
screw-in (sealed with an 0-ring) compression gauge. With a couple of revs, the 
readings on all cylinders were a fairly consistent 95-100. But, if I continued to 
crank the engine, the compression reading on several of them could be pumped up 
to 125+. What, if anything, could this mean? (Plugs are carboned up a bit, but 
nothing serious or wet.) Engine does not "smoke." Another out of sorts thing 
I noticed was a very oily pcv pipe (PG trans) and some oil residue puddled in 
the "duckbill" in the top of the carbs. (Worn rings??). I'm not sure of the 
mileage on the engine as the odo reads 12K, but that is almost clearly neither 
original or 112K.
Thanks,
Grant