Well i had a CEL for "high idle" after i put in the 2.3. Ran good still...more pull, i was happy. I now have to get it inspected so had to install the old tb back on...damn it sucks lol. I miss the pull and my exhaust sounds a lil different. I noticed when i took off my tb that you could see light through the middle of it...around the butterfly. So i am guessing that this is where my high idle was coming from by allowing air to go through at idle.
good luck man, I'm on my process of doing the 2.3 ho t/b swap too.
shouldnt make much a difference... i have light on my stock 52 one...
usually the pintle for the iac makes the most difference on tb choice...
I recommend that you VERY VERY carefully center the throttle plate in the bore of the TB.
Back in another life I used to trick out Quadrojets, don't laugh - will stomp any Holley ever made. One of the MAJOR things, amongst many others, was to get the throttle plates centered. Made MAJOR gains on performance.
If the throttle plate is not centered properly you have unmetered air getting into the engine. Think of it as a good size vacuum hose being off.