Its fairly easy to find the id stamp on the IH sixes. Its stamped into a flat surface at the right front corner of the block just below the head and exhaust manifold. Might take a little work with a wire brush and a trouble light to see it but I have it on all of mine. Originally posted by Ralph Goff and edited by Jim Hadfield.
The engine info is also listed on the id plate on the drivers door too. It’ll have an engine number there and you can see if its the same as the number stamped on the engine. The above would apply to the SD and BD engines. The GRD-214 and 233, along with the RD-372, 406, 450 and 501 are on the driver’s side of the block, just below the head. The BLD series engines have a cast insignia on the left rear side behind the oil filter housing. The engine number "BLD xxxx" is stamped on a raised boss on the left front side of the block. Please let me know the id method for the other engines too.