Compression is off

[sleeperstang]

Guys,

My rebuilt engine has had a sort of vibration/unsmoothness to it
since I've had it. I went and talked to the guy at the automotive
balancing shop and asked for his opinion. He suggested it felt like
a dead cylinder or something of the sort and not a "mechanical"
problem with a bearing nor a balance problem. A friend of mine had
suggested the same thing. I checked the ignition (wires, cap, new plugs: all good) and finally got around to doing a compression test on it yesterday. The driver bank (this is a 302 w/28 oz imbalance) had an average of 206.5 psi, while the passenger side had an average of 188 psi.

I'll list the numbers in case anyone needs a better visual.

Driver Side Passenger Side
cyl 5 = 187 cyl 1 = 210
cyl 6 = 192 cyl 2 = 200
cyl 7 = 190 cyl 3 = 208
cyl 8 = 185 cyl 4 = 210

I imagine the machine shop milled one head more than the other. Does it seem possible to any of you that this difference in
compression would give off this "dead center" effect to the engine? Anyone had an experience of this sort?