Cylinder 8 not firing

1973 Duster
318 stock heads/cam
Performer intake/4 bbl

In preparing to do the next stuff (heads/cam), I decided to do a compression test to make sure the engine seemed healthy enough to warrant dumping more money into it.

It sounded like a cylinder was missing - car has been sitting a while but I start it up a few times a month. I pulled off spark plug wires one at a time, listened for the engine to change, and replaced them. #8 is not firing - no change in sound or vacuum when I pull off the wire.

Vacuum is reading 15-16 inches (needle sort of bounces between 15 and 16).

Compression test results:
dry/wet
1: 155/175_____2: 160/180
3: 155/160_____4: 159/170
5: 160/172_____6: 160/169
7: 160/175_____8: 165/177

I feel like the valves must be sealing to put up those compression numbers.

After pulling the valve cover and rotating the engine, I can see both intake and exhaust rockers going up and down like they should.

Ideas?

EDIT: forgot to mention that I got a strong spark from the wire and sparkplug is firing (outside of the hole)