GMC made a kit in the 60's to repower early 50's GMC trucks with a V6 so it has to be doable. All they did was fabricate motor mounts. I don't know what they did with the steering box. The steering box is a problem with a V8. I have only actually seen one. The GMC dealer here did the conversion. The owner didn't keep it very long. He bought a Chev with a 409. Wasn't very long, he fell asleep, hit a tree and killed himself. I don't know what ever happened to the converted GMC.