Opinions

My 383 is freshly rebuilt, all good internal parts, mild comp cam, weiand manifold 1406 Edlebrock carb HP exhaust manifolds
Ive felt its not running right, ive thought a vacuum leak as it did have a vacuum leak on the intake manifold but its still running to rough, car has a shake to it and ive turned over every stone
Today I put vintage Snap On cylinder shorting meter I have and I found something interesting.
The car fires on all eight for sure, there is no hesitation but again idles to rough
1 3 5 7 when shorted one at a time gives a noticeable drop in RPM as I watch meter
2 4 6 8 also give a drop but not as much as the odd side, close but not as much
Now the meter also lets you short the 4 odd plugs and 4 even
When I short the even big drop in RPM but engine still runs
When short odd engine just about stalls out, barely runs
There is a very noticeable difference in the odd side head and even side head
Im thinking I have to do a complete compression test asap
What do you think? And off course thanks