IDCR's and their effect on deceleration enrichment

[Cadman-iac]

   I'm currently using a 17057512 on a 350 with a 9.35:1 compression and stock TBI heads, (don't say it!) I should have used older heads but my intention was to go stock and use the TBI, but the roller cam wouldn't play nice with the computer, so 1 lobotomy later I now have a Q-Jet on an Edelbrock air-gap intake.  (I figured if I'm going old school, go all the way).
 I told the machinist what I wanted to do and he suggested a roller cam and flat-top pistons that would work with the computer. (I should have ordered it all myself but thought he'd been doing this for years, he knows what he's doing,  RIIIIGGHHTTT!!!)
  Anyway,  the CompCams specs are 206/210 @ .050 with an LSA of 112°. It runs really good, just don't want to fry it by not getting the AFR right. The computer couldn't do it without a modified chip and who knows what else. $$$$$$$$

  I don't know if I have this right or not but here’s what's going on.
 I have a really good AFR on idle and during cruise mode, but when I would release the throttle the AFR  would go extremely rich (for about 30 seconds or so) to 10.0 then it would settle back to normal, around 14.3-14.7 roughly.
 I tried adjusting that out of it with the mixture screws, but that really only messed up the idle, it didn't effect the deceleration AFR.
 So I figured that maybe the IDCR's were too big causing it to draw more fuel from the idle circuit on decel, and I should use smaller ones.  It has  .056's in it now,  if I reduce the size to  .048 and raise the APT a bit to compensate for it would this work?
  Here's the complete specs on the carb as close as possible:
Carb# 17057512
 Idle tubes-  .035"
IDCR-  .056"
UIAB-  .070"
LIAB-  .062"
Bypass air- .099"
Mix holes-  .080"
Float- 15/32"
UPAB- .050"
LPAB- .064"
JETS- 73
Primary rods- 49M
Accl pump noz.- .025"
Sec. rods- DP
Hangar- K
Sec.air tubes- .038"
Sec. well holes- .039"
Air valve spring- 7/8 turn
Sec. actuation lever- long
Power Piston spring- 4"-9"
APT set @ 2 turns up from bottom
Accl pump lever hole-  inner

 Am I on the right track, or all messed up? Please advise. Thanks.

[quadrajam]

The momentum of a decelerating vehicle will drive the engine faster than the Idle
throttle position normal speed. The stronger vacuum will pull more fuel from the
Idle holes and lower part of the transfer slot with little additional air hence the
brief rich reading.  ...did that make sense?...I just got dizzy rereading it...

Anyway nothing to worry about. Try coasting in neutral and see if it goes away.

[Cadman-iac]

 Those gas fumes will do that to you, lol.

 Thanks for that, I knew it was pulling from the idle circuit, but I didn't think it would cause that much of a change to the AFR in this situation.
  If that's normal then I won't worry about it. I haven't used an AFR gauge while driving before so I'm not used to seeing the fluctuations. Just trying to make sure I'm not going to damage the engine from miscalibration.

  Are my specs in range, do I need to change anything?  Thanks for your help.