Need some old timer advice please,

As some of you may remember a little while back I brought home a 372 Pete. My plans for this truck are to turn it into a straight truck 3 car hauler, basically it will be used as a shuttle or final destination del. truck for my semis when they bring loads back into kansas with a couple of stragglers on that would take them way out of there way without any hopes of a reload.

So here is my dilemma truck has the original BC4 NTC 315 and direct drive 9 speed, both are very low mileage units and the motor runs excellent, truck is on lopro 24.5 with 3.90 rears, so 2000 rpm is all of about 61 mph.

I really dont want to change out the pumpkins, and I need to be in the 70+ range, so i am looking at two options, both are a bit out of the main stream but i have my reasons.

First option would be to swap out the 9 sp for a super 10, reason for this choice is it gives me a .75 over which i think will get me to 70 at about 1700, also i am simply not a big fan of the no feel cable shifters and this on needs work, so the less times i have too move the stick the better, I have had a super 10 in the past and found it decent after i got used to it.

Second choice is an Allison MD3060, 6 sp full auto has a 1 to 14th a .75 5th and a .65 6th, this would put me closer to 1500 at 70, i know everyone always says dont run the big cams to low on rpm, but i think 1500 would be ok? Dont forget max weight of this truck including cargo would never exceed 44,000 pounds.

Both trannys should be fine as 315hp and 1250tq is within even the automatics range.

I am leaning towards the auto, found one for a good price and it is exactly the same length as my 9 sp, also getting rid of the cable shifter and taking out the clutch pedal would give me some nice floor space.

As far as I can tell the allison carries its own ECM and only requires batt power and a TPS switch under the throttle to work. Have at it, all opinions welcome, thx