['68OrangeSunshine]

I heard GM Brazil used Q-jets on L6s. Of course they use sugar cane alcohol for fuel there and a much higher CFM is required for pure alco than gasoline.
Santucci's book, "Chevrolet InLine Six Cylinder Power Manual," shows an 'Experimental Chevrolet (never released) four-barrel manifold for Quadrajet carburetor', on page 115.
Personally, I have an Edelbrock 1404, 500 CFM squarebore [AFB clone] on the 4 -hole Offenhauser intake with Clifford headers, on my 292 in my '68 C/10 Stepside. I replaced the '68 rod-and-bellcrank linkage with an aftermarket throttle cable. Much improved.