I have a Factory rebuilt carb, this was rebuilt years ago, It came from a local auto parts store and I did test it, and it works great and no leaks or anything, works and looks like it came right from GM, It has the Tag still on it, GREAT carb, It really looks PERFECT and runs like it should. This should be the correct carb for a 1963 buick riviera, Electra, Wildcat, and a Lesabre. Mike 314-420-0410