I believe the serial number is American... although I am not sure. As said before, you could put any 216, 235, or 261 in there with little or no modification, or any 228, 248, 270, or 302 with little or no modification. Find an engine that makes sense financially. I personally would try to find a 270 or 302, but a 235 high pressure or 261 are also good choices. the 216 is a step backwards in the old gmc.
