[TheDark1]

Welcome, I do believe you are correct on the radiator. All of the ones I've seen were like the square one, with a top and bottom bracket to hold it in place. They may have had some cross over to other years though, I'm not an expert on anything. You'll need to get numbers off of the block and post them to have an idea about the engine. There should be a flat pad on the passenger side of the block by the head, under the a/c compressor, with some numbers stamped into it. Post all of those and someone will be able help. Nice truck, a '66 big window with A/C and V-8. Cool....
Oh yeah, if you need help or info, ask before you break something. If you don't, everyone will point and laugh. Just kidding, everyone is here to help each other.