440 Six Pack Carburetor Question

Thanks yall. Chris actually lucked up and found one on the B bodies site. I'm still in shock. The guy said it was on a carburetor on a 68 Mustang with a 390 but it was on the rear of the carburetor. He said he knew what it was because the fuel inlet was on the driver's side. lol All he wanted for it was a good secondary float bowl which I am sending.