Steam Driver

In my search for a replacement CIS fuel tank (for '82SC) I have come across tank where the return line inlet is a slip fitting (i.e. hose and clamp) rather than the screwed-down, tapered one that my tank has (had) that mates with the female side of same on the return line. Any idea out there what that tank is for? Is it usable with my car which has the screw-on fitting by altering return line? I can see how the screw-on is better, but obviously the slip on must have worked as well.