These new gaskets fit 4160 Series 550-600 CFM Holley 4 barrel carbs with vacuum secondary, 1-9/16" throttle bores and non removable jets in the secondary. List #'s 1850-9^, 1850-10^, 1850-11^, 1850-12^, 1850-13^, 1850-C^, 3810^<, 3811^<, 3814^<, 3815^<, 3836^<, 3837^<, 3838^<, 8408^", 8409^", 8410^", 8411^", 8412^", 8414^", 8415^", 8416^"", 8418^", 8420^", 8421^", 8422^", 8423^", 8424^", 8589^, 8590^, 80457-5^, 80457-7^, 80457-8^.
