Doesn't the 58mm TB have those "V" grooves on the backside of the TB that bypass air from fully entering the IAC hole on the factory manifolds?

http://members.***.net/chipsbyal/page/idle/tbi.htm

If you have that "V" for the IAC, then you wouldn't get full IAC air to the manifold anyways. Right?

 

I read about that but it wasn't a Holley. Can't recall what the back of the Holley looks like but at this point I don't care to pull it off just to check. See below.....:-)


ITS FIXED!!!

I adjusted the TPS one more time and got the counts down to around 48. Went for a drive and the hesitation is 100% gone and it's pulling much harder now that the AFR is back within reason.

After that drive I put the plate back on and checked the counts. Not sure how, based on the size of the IAC passage in the plate, but the counts are now at 25, no hesitation, and pulling harder at WOT.

Also figure out that my tune was setup for 36# injectors and I have 42s. Never had 36s so I assume my tuna just f'd that up. Explains why it's been so rich and down on power.

Now I feel like I can hit it with the new Nitro Dave's plate kit without being concerned about those issues causing a problem.

I couldn't be happier, thanks for all the suggestions.