I have included 2 pictures of distributors both commonly referred as "49-53 Ford 8BA flathead V-8" Can someone please educate me... The one with the smaller diameter shaft fits my 1952 F-1 Pick up.. I received a replacement, but its different, fatter shaft with the gear at the bottom. Is it just the front cover that is different? And does my style have a name, so I can get the appropriate fitment?