I've tried that setup on my A.
As ken ct stated, the end cylinders run very lean.
Could never get the Holleys to meter correctly, finally switched to 97's.
When running twin 97's, could never get the end cylinders to color the plugs.
Changed to a Thomas manifold,(larger plenum) twin 97's, front carb opens about 10% before rear. Both carbs used for idle. Adjusted jetting with a wide band O2 sensor, idles hot at 11.8-12.0 afr.
Can adjust idle to 14.7, but no off idle throttle response, too lean.
My engine has an actual 8:1, Lion head, headers, MSD.
Also, my engine loves timing, something you will want to experiment with.
Ken