Holley one barrel to hot...

What is percolating?
If its in the fuel filter that's normal.
Starting in '63 Chrysler posted this
Carburetion and Performance Diagnosis (Session 188) from the Master Technician's Service Conference

They also did some subtle things, like this (1970)
Heated Air Intake and "Vapor Saver" (Session 271) from the Master Technician's Service Conference