Well it is still a usefull number whether its a list number or model number ( which is the same thing to me , I sell appliance parts all day , and worked auto parts before too ) , for example say if it says 0-1850 ( ran on my 76 chevelle ) then we'd know its a 600 cfm side hung 4160 with manual choke and could get a rebuild kit for it /forums/images/graemlins/k5.gif /forums/images/graemlins/k5.gif