I don't have a 313 or 318/727 but was talking to Ted Playford today and he has 3. He has never seen one from the factory with the kickdown linkage. Bombardiers came out that way and they seem to be fine. I notice one of his shifts at a bit higher rpm but still not terrible. I suppose bombardier was mating up the engines they had in stock (318's by then) to the heavy 727's with the brake on them. and likely would have had to go to a lot of problems to set up the linkage, so they just locked them ahead. As someone pointed out here, this application is different from a car or truck on the highway so likely wasn't needed anyway. Appears old man bombardier was right again. On the other hand if I was installing a motor/trans out of a car or truck, I'd leave it on. Ted says not to leave them loose,especially on the fords as they will lug and not gear down. If locked down they seem to work also.