Besides the marketing aspect of Loadflite ( after all, in a truck the name inspires an extra level of hauling ability ) in those days when every car maker had some type of O-Matic or other futuristic sounding name for the features of the car, the two transmissions are basically the same as Rodger noted. >From a practical, dirty fingers and skinned knuckles aspect of them, after the aluminum case appeared in 62 they were the same. I believe some had a shorter output shaft and case depending on the truck they were to be installed in, and this is a stretch of memory, some also had provisions for retarders ( a type of braking device to alleviate some of the work on the service brakes ) Mikey 62 Crown Coupe