1974 K5 full size Blazer fuel tank and reciever hitch
 

Just an FYI to save you the headache I got. The K5 Blazer came with either a 20Gal, or a 32 Gal fuel tank: Chevrolet K5 Blazer Specifications

Not knowing that, I purchased one online and what they are selling is 25Gal, not 20 Gal replacements. No big deal unless you have already purchased a Curt 13401 Receiver hitch. Now to make this fit I have to cut square tubing as a spacer between the hitch and frame to make the hitch fit without hitting interfering with the fuel tank. Not really what I wanted to do, but it will save me the cost of shipping the hitch back and trying to figure what one will work. That's the way it goes sometimes. At least somebody now has identified this for you so you don't have the same situation.

Well what a dummie I am. I thought the cut out in the hitch sides were to go over the rear leaf spring mounts. DUH. This does fit as advertised, sorry for misleading.