I have encountered several M6SA Linkerts,
but never a BA.
(SA referred to the military fuel filter fittings.)
Beck never made carburetors.
I believe they were re-stamped for the aftermarket by L&L, based upon an L&L spec sheet for the M8SA.
Knotthead's second link above is fairly accurate.
The first is fraught with misinformation, and models that never existed.
Virtually any 1 1/4" model Linkert can be applied to a Chief, if if properly prepped, and Chief guts put into it.
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