Leaking Venturi Boosters / Edelbrock Performer 1404

Did not see a "Flapper Valve" on the passenger side exhaust system, maybe that is specific for certain year cars??? Did find it interesting the car had a 195* thermostat which I think is a tad too high, also seemed to open erratically when put in boiling water. Dunked it three times with three different results, 1st time didn't open, 2nd time partial opening, 3rd time fully open. Going to replace it with a lower temp t-stat and hope water will flow again through the radiator. When I drained the coolant it had zero rust or particles in it so I think the radiator is in good shape. Do think the erratic t-stat might be contributing to a possible heating of fuel in the carb.