Could anyone tell me if there are two versions of the older 7.3 non-turbo diesel engine? Or, was there a year when they changed them? I need to replace an original 7.3 in a 1994 F450. I found another 7.3, but it looks different. It says 7.3 on the valve cover and I don't believe its an even older 6.9. I found some pics of an International version that looks like the one I am purchasing. I know International made all of them, I just wanted to make sure that it will work. Is it possible that this was a bus engine or something other than a truck? It's actually coming out of a Ford truck, but I don't know what, if any, mods were done to get it in there. Any info you have on this would be greatly appreciated.