If it were me building for street use, I'd use a Holley-style center pivot carb in the 600-650CFM range on the 5.0, certainly ask the advice of the cam manufacturer....or get a custom built QuickFuel from blykins.
The 5.0 in mine ran like a dog with a Holley 780CFM (#3310)....runs like a scalded-assed ape with the Edelbrock 575CFM Thunder Series carb (totally street driven, though) !!
Sounds like a great motor you're building there....ought to be really tractable, as well as trackable, with that EFI setup!!
Cheers from Dugly
