On the IAC, I see it now. The currently available remote IAC solution from Holley is: https://www.holley.com/products/fue...per_efi_service_components/parts/543-122 Very cool. I just learned something. I like the way you built it into your system. Not sure if I'll ever need a remote IAC but if I do, this Holley part is a possible solution.

You and I came to the same conclusion on parts many (like 15 or 20) years ago. I have the Mallory 4309 currently in use on my carbureted wedge motor. I have the low pressure bypass spring in there and it's set to 6-1/2 PSI. I forgot that this regulator has another EFI spring kit that allows ~50PSI. I remember buying it back in the early 2000's timeframe thinking that if I ever went to EFI, I could swap springs and use the same regulator body. I think I still have the box that regulator came in and the EFI spring kit is in there. But times have changed and the technology has improved. I plan to run the Aeromotive 13305 regulator on my in-process EFI build. I have a FAST regulator which I'm sure is and OEM Aeromotive part that was bundled into a FAST EFI Fuels system kit. The FAST branded regulator has a -6 ORB return port and a small orifice. The Aeromotive #13305 X1 Series – EFI Pro Return Style Regulator has a -8 ORB return port and a 0.313" return orifice. Aeromotive says it can bypass 250GPH with a -8 return hose. If I hadn't already spent the $$$, the best choice available from Aeromotive is part# 13134 - Extreme Flow 2-Port EFI Regulator which also has the 0.313" return orifice but advertises it as "high flow". The 13134 regulator body is a bit taller but can take a super high-pressure spring (75-120 PSI).

Pictures are of the Mallory 4309, Then the FAST and Aeromotive regulators. Last pic is the shot of the return orifices (FAST on left and Aeromotive on right).