Texas used the engine number for titling until the mid 50's. I have GMC trucks titled by engine number up to 1954. I have some 55 Fords titled by chassis number so it seems like that may have been when Texas made the switch. If you don't have the original engine, there is nothing wrong with changing the engine number to match the title. In fact, I would recommend changing it to match the title because Texas has no provision for altering titles. Altering a 17 digit vin number is illegal. Texas law does not address chassis numbers before the 17 digit vin with the 10th digit indicating the year model became the national standard.
