Some decoders I've found say it's a 6-cylinder and others say an 8-cylinder. I wouldn't be surprised to find it's not the original engine but why leave the 2-speed tranny if you're swapping an 8 for a 6? (money comes to mind)
Hmm. Well, regardless, I want a speedometer that works. I'm probably going to replace the 2-speed with a Turbo 350 or 400 and put a floor shifter in it so I assume that will change things again ;-)