Any carb guru's that have paid attention to the Casting numbers and details of the AVS top with respect to the actual carb bottoms they go to? Carter gives data on the bleeds up to about 1969, but after that no specific info, plus they don't spell out anything about the idle compensation check ball.
I have seen minor differences in the check ball assembly, differences in external fuel bowl vent holes, and even one with a significantly smaller secondary anti perc bleed.

I have seen top casting numbers 6-1886, 1924, 1931, 1944, 1945, 2004, 2020. Some have been on carbs I do not believe they go on. So not sure if any of the restorers or detail guys have paid attention to this. The most common tops are the 1886, 1944, 2020, which seem to flow 68, 69, 70-71 I do understand the vent tube for the ECS cars in the 70-71 time frame and the accelerator pump lever vent in 68-69, these other external vent holes are different.

Also, I have seen reference to a 3-4 page Chrysler AVS modification instruction from about 1973. Does anyone have a pdf copy they can share? Thanks.