[Gaz64]

Tom,

If your carb flows identical for each pair of barrels on a flow bench, then I'd say you have piston ring issue in the "low flowing cylinder".

Doesn't take much in blowby percentage loss to affect cfm readings as measured with a carb balancing device like a Unisyn.

Twisting the shaft to favour the low cylinder may or may not increase that cylinders flow rate.