I have been using my Sniper since 2017 and really like it. Its been on two configurations of my 390 both with Performer RPMs. I do run an open spacer though (did with my carbs too). I also use a fixed orifice PCV. My first cam was a 110* split and made 6.5" of vacuum with carb and 7" with the Sniper. It operated fine (better than any carb I had on it) with no need to open loop the idle and off idle areas. I do not run ignition control as the cost is prohibitive and my optical trigger generates no EMI/RFI issues. Suggest you post your datalogs and config on the Holley EFI forums and get some opinions. Cant hurt.
 

I used 1 piece .120 wall Smith Brothers push rods. Looking at the ARP studs on the driver's side there are some shiny spots on them signifying wiggle. The passenger side looks totally normal.  I think new studs and some additional clamping force should solve the issue. I hope!!!

Can't argue with your results, but I can say, having ignition control makes it significantly more adjustable and can make it better

I have heard of the dual plane issue, but haven't seen it.  That being said , I generally notch the dividers anyway with a dual plane, so it may be why.  However, assuming the IAC doesn't make a vacuum leak on only one bank, it shouldn't cause an issue, but I have heard it.

As far as LSA over 110, doesn't compute for me, every single EFI engine I do is over 110, (my Mustang is 110 LSA, 72 degrees overlap but also Mass Air Flow equipped) but LSA alone doesn't matter much, it's really how much overlap.  I could buy a typo that excessive overlap for tighter LSA could screw with idle due to unburned fuel in the exhaust, but not greater.  Would be interested in what you saw on that.

You make a valid point though, 50% of the builds I do are carbureted with standard ignition curves and they do great.  However, so does EFI, but once you start understanding the programming, you can do magical cheetah flips with timing and mixture in a variety of situations with EFI.  Do you NEED that?  Not necessarily, but when you do, it's real nice.

Don't get me wrong though, I agree on your experience, 1200 bucks worth of stuff, maybe 2000 when you add ignition, plus more high pressure fuel changes.  Someone really has to have a desire or need, if you don't, it's a lot of money

i broke a tip off one of my pushrods and the problem was my pushrods were a hair too long and it caused one of the cup ends of the pushrod to hit the rocker body.

IAC Hold is where the IAC parks once you give it throttle, if it's too high it won't idle down easily

Ramp Decay is the time it takes to relax from the hold point once the throttle returns

RPM above idle is where it starts to settle

RPM above idle to start idle control is when the IAC takes over actively, not the ramp down

I think your idle speed to start ramp was high, and you went higher. That will essentially ease the idle starting at that point

However, logs are your friend, going to need to get that working again to really figure it out

I did test the idle speed to start ramp parameter down to 500 to see the effect (1325 total).  It resulted in an angry, erratic idle of about 1400rpms, like the engine was loading up to launch.  So, I changed it in the other direction to 1250 (2075 total) and it settled down immediately as IAC dropped to 0%-2%.  My idle is set at 825 in neutral, about 7xx in gear.  Any higher and it diesels at shut down.  Any lower and it shakes the car apart and feels like it's going to stall out at red lights.   

I agree, I need to get that laptop fixed so I can datalog.  Microsoft has been awful lately with pointless and damaging updates (practically every phone call I get on for work has someone mentioning how recent updates wreaked havoc, but I digress...)

What would the negative effect be if the idle speed to start ramp is set far too high?