"Baselining" my 225

From the 1980 truck service manual. The 225 cubic inch engine will carry an identification number as follows:The first position will designate the model year. The three numbers following the model year indicate the cubic inch displacement,(225). The letter following the engine displacement designates usage,(T)_Truck. The following numbers indicate shift build and day and month build date. Letter after that indicates oversize or undersize component parts. So your engine is a 1980 model. Some of the numbers following the T may not have been clearly stamped, which is not unusual.