Chrome AC compressor info needed

[4shongo]

My AC compressor went out on my newly purchased 75 C10 stepside. I would like to replace the big factory compressor with a smaller chrome size (R4)?. Anyone done the swap? Is it a direct bolt in? Any issues with the line set? Brackets? Trying to get the whole story before I start ordering parts. It was converted over to 134A years ago so that part was done. Or if that is not possible (changing to a small compressor for not a lot of cost/effort) what about a source for a chromed factory compressor? Thanks guys.