Dan, The SPEC number on the tin applies to the original engine only. If you think your engine has been short blocked then look for an ID tag identifying the specific short block number. On most of the blocks I have seen the tag is attached by one of the bolts securing the engine base flange. The SBV 231 (VH 70) cast iron short block was the one recommended by John Deere once the model 70 went into production. Prior to that there had been a VH 60 short block available but I do not remember what the SBV # was for it. With a short block you would use the SBV number to look up internal engine parts. You would use the original SPEC number to look up any parts that would have been transferred to the short block (flywheel, ignition, carb, etc).