Hi guys, I've bought a radiator cap off E..y that said it fits MB cj2a cj3a m38 etc but it's way to big to fit in the neck, my 3a has a std neck that you would see on most cars with a 7 pound cap, is my CJ3A sporting the right neck or is the listing wrong - I don't have another jeep to compare it with, thanks Steve in Australia...