The IAC counts are programmed into the ECM so that when you turn on the AC, they compensate. You can adjust that or remove it via tunerCATS / lt1edit

 

When I switched to the AS&M monoblade I also switched to a larger converter at the same time. Went from a 3600 to a 4400. RWHP gain was 10hp, I'm sure some of the gain was masked by the larger converter. The previous TB was an AS&M 52mm. Before & after dyno pulls were with in 24hrs of each other.
I didn't experience any idle or low speed driveability issues with the big TB. I highly recommend it for big cube & high RPM small cube applications.
Steve...