IDF manifold for Big Block

Webers are fantastic , also available in 48MM venturi , if you buy the 48s you can put a smaller venturi in for tuning.
With a 48IDA fitted with a 42mm choke each barrel ( according to research on a flowbench ) should feed 330 cfm
more than enough for a Big Block , this setup was used on the IMSA Greenwood Big Block Vettes.
I ran Webers (2 side draft 45MM DCOE) on my GT-4 car , the closest thing to fuel injection you can get.