I made my living with 30+ year old trucks. I don't think that is really the biggest issue. Once you get much above 120K lbs it gets hard on driveline components, Yoke spread, U joint needles wear into the hard surface, etc.
problem gets worse when you don't have enough power to get up near 1:1 ratio out of the transmission. Rear axles are fairly robust, but the transmission is the weak link. Having to spend all the time with the transmission in reduction, will put a lot of heat into the oil.
You can somewhat offset these issue by have a low enough rear ratio so at highway speed you are at the redline. OR, two speed rears so you move some of the torque multiplication back so the driveline doesn't carry all the torque load.
There is some evidence that with single reduction rear axles when the you go slow ratios, there is less gear contact with the fewer teeth on the pinion then when faster ratios are used, making them weaker. 2 spd or double reduction help here. In reality operator will make the biggest difference. That includes "rating" of the components.
You did say 350 hp, so that what I was commenting on.
If I were spec'ing with 30 year old spec's to pull that kind of weight all the time, I would spec 2 spd rears, carefully choosing the ratio to work with the transmission and engine. So likely a 13 speed underdrive and 2 speed rear axle, or may be a Spicer box up front. 400hp mechanical turned up slightly, larger than "normal" radiator. These are not normal highway specs for a Super liner or really any truck. The Mich trains pullers were not "regular" tractors.
I didn't pull 160K day in day out 5-6 days a week. I was up in that range very rarely, and it took its toll on components.