The Rochester 4 jet is a square bore if I remember right, I don't know the bolt pattern but I would think the most direct fit on that manifold would be a Holley square bore, many available with manual choke. Check with Summit or Jegs for an adapter if needed. My preference would be a stock spread bore GM manifold and a Q-Jet.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy