340 compression variance

Long time since I've been on here. Spent the last 9 years building my house so no time or money to work on my car until now.
I plan on pulling the engine out and freshening it up. The car sat for 16 years before I bought it in 2005. The previous owner told me the engine was built by a local machine shop for Friday night drags. They are now out of business.
Anyways, before I yard it out, I did a dry compression check on all cylinders warm, and have variances. The lower ones I checked again with oil:
1. 180. 2. 170
3. 180 4. 170
5. 160. 6. 150
7. 170. 8. 170

#5 was 180 with oil, and #6 was 160 with oil.
So the question I ask is, what do these numbers tell you? High compression engine but #5&6 rings getting worn?
I never had blue smoke with this engine but would sometimes get oil out of dipstick tube at high RPM highway speeds. It has a PCV valve and breather on opposite valve covers. In the past I had a hard time dialing in the timing and carb, I believe due to a vacuum leak. Vacuum was erratic before and never higher than 14". Smokes gray a lot, runs like crap. I managed to limp it into the shop tonight for winter rebuild. The block is a 73. Sorry for long post but would appreciate some input. Thanks in advance.