No mystery. Here’s how it worked: Engine blocks were cast at the Rouge Plant without any serial numbers stamped; those came later. Blocks were set aside in a hold area to cure for 30 days. It’s just the nature of the beast. Cast Iron requires a 30 day green period of which to cure otherwise it is too brittle to machine. It is similar to seasoning wood. If you cut green wood, it won’t burn. It must be seasoned for a period before it will burn. The next step is to pull engine blocks that have cured at random from the hold area to the machining area. Engine blocks get fully machined, cleaned, and then set in another hold area, still unmarked. Next, blocks get pulled at random to the engine assembly area where they are fully assembled and sent to yet another hold area. Once assembled, engines get pulled at random to the QC Test Area where they are put on special machines to be fully tested for function and gone through a break-in period. If and only when the engine passes QC Inspection/Testing is it then given a hand stamped serial number and gone to another hold area at random, to then wait to be pulled for final assembly on the line. Serial numbers are stamped in sequential order, BUT they are not maintained in any particular sequential order. A functional, assembled QC approved engine was of no concern to staying in any particular order. If at QC Testing an engine failed, it was either sent to a repair shop and retested or if unusable, would be scrapped out. Its only purpose was to ID the engine block whose serial numbers were technically meant to ID the vehicle serial number. Since many blocks were swapped out, a 1956 s/n engine block could have been switched out to a 1958 tractor. Go by the manuals and what your model has. Note the date on this Service Bulletin. S/N’s were used on all Ford engines, not just tractors. Also, the capital letter ‘I’ was used for the numeral ‘1’; the lower case letter ‘b’ was sued for the numeral ‘6’ and the inverted ‘b’ was used for the numeral ‘9’. Before April, 1950 cylinder liners were made of steel and thus stamped with a STAR (*) prefix and suffix. Post 1950 Ford changed to cast iron sleeves and then changed to a DIAMOND (<>) symbol.
FORD ENGINE BLOCK SERIAL NUMBER IDENTIFICATION:
FORD N-SERIES TRACTOR SERIAL NUMBER LOCATION:
FORD 53-54 TRACTOR SERIAL NUMBER LOCATION:
FORD HUNDRED SERIES TRACTOR SERIAL NUMBER LOCATION: