Engine miss

[Kahuna]

Guys
I have a 1939 Ford that I'm working on in an attempt to remove a slight miss that occurs at all engine speeds. So far this is what I've done:

1) rebuilt carb--no change

2) replaced all eight plugs--no change

3) ran a compression test-
results:

Cylinder #

1) 85
2) 85
3) 88
4) 87
5) 82
6) 85
7) 80
8) 85

4) Helmet distributor, 12 volts along with coil

Converted to electronic and tested OK on machine to 5000 rpm- no change

5) replaced plug wires- no change

Next area I will address is the distributor end caps, as I've seen a problem there before with carbon tracking and cracks.

What I'm wondering is about cylinder #7 being a bit low at 80#?
I wonder if I could have a sticking valve that didn't show up during cranking test?
Would this be something that Marvel Mystery Oil might help? I've never used the stuff, but the engine hasn't had anything major done to it in over 47 years.
Just thought I'd ask

Thanks for any thoughts/experience.
If the distributor caps don't fix it, I'll just start drinking..But,
I'll check back in if that fixes it.
Thanks
Jim