The Power Wafer make a great tow rig. 4.1s or 4.56s. Need to slap some extra springs in the back, but the 456s make up a lot for the poor gear splits.
They doo call them 6.4s though because that’s what the fuel mileage gauge goes to once the trailer hitch is locked to the truck.
Kind of of topic but pertinent. The newer GM 6.0 HDs are POOCHES!!
Always thought it was because theones I drove were old and ragged out 4 speeds.
Just towed with a new 6.0 2500 with 4.10s.
4500lb trailer with about 7klbs of steel on it. On a mild grade too (snoq Pass). My 2016 5.3 1500 will out pull that 6.0. No questions asked. 2500 has more chassis of course, but dayum......I was not expecting that.