Just finished putting multiport EFI on a 66 Vette 427 (all restored, rectangle port engine, show winner) and used the Holley HP efi system..... what a treat. That is a great EFI system.
This thing is POTENT now, and runs absolutely amazing. Oh and we added water/meth injection too.
Biggest thing was fitting it under the stock hood, as you know BBC single plane EFI manifolds are not a nice thing to fit under the hood, so we took a shot in the dark and used a performer rpm dual plane and machined it down and put injector bungs in it........ I know I know, but it actually works great!!!!