OD trans

Agree. Same with the 500 and 518 trannys. They are 4-spd trannys, not 3-spd with overdrive. A 727 with a GV OD is a 3 spd with OD. With that setup you 1st and 1st in OD. With the 518 and 833OD you don't.
Correctomundo as the Fonze would say.