In my Mainship I have Walter RV40 V drives then Borg 72C's attached to the motors. The Walter V drives are really built well and heavy duty. They are very heavy. I guess I'm trying to say the 72C and the RV40 V drive are seperate units. I bought 2 new RV40's when I repowered in 2007 I think it was about 8K a side one needed an idler because my 496HO motors didn't come in R/L configuration. You can't run a transmission in reverse all the time it will burn up. (This probably doesn't apply to you).
Bill
Bill