The 4150 4-barrel came out in '57. I
thought I read many years ago that one of the Edelbrock techs came up with the "modular" idea that also was applied to the 2 barrel 2300 series. The 4150 has primary and secondary metering blocks that contain the jets and power valve(s), while the later 4160 uses a secondary metering plate with drilled fixed jetting. Great carbs I still use.
