1920 Economizer Valve

I know you can find photos here if you search the fuel forum. There are 2 fingers on plastic lever that the vacuum actuation rod acts upon, which open spring-loaded ball ports at different times, hence the "2 stage". It richens the mixture at high throttle for more power when needed. The "economy" is when it closes. Same idea as the "power valve" in 4 bbl Holley's, but not replaceable (for tweaking), and I haven't heard that it is damaged by back-fire like power valves often are.

im sure it could be, there is just a port thru the body that goes to the backside of the valve. and yes it is tweekable by cutting coils off the spring or filling down the arm, even filing on point to make one come in later.