I have a 2020 Newmar Canyon Star 3710, which is 38' long & on a F-53 26,000 GVWR chassis, & a V-10! It performed pretty well, but I added the "Ford Ultratune" from Ultra RV and it made a substantial difference! I'm not sure about all the "HP" increase claims, nor the "fuel mileage" claim, but I do know it had to help the torque situation, & the transmission shift points!
Why, because it does accelerate much better when getting up to speed, turns about 250 fewer "RPM's" at the same road speed; but upshifts & downshifts fewer times under load, such as going up a decent grade, or on a mountain!
I do know, it did not improve fuel mileage! 6.8-7.2 towing a GMC Terrain, & 8.2-8.5 not towing. Overall improvement on a 1-5 scale; I'd rate it 3.5 to 4.0!
Had an '04 Newmar Mountain Aire 38' on a 22,000 GVWR Workhorse chassis with the GM 8.1 engine, no engine performance chip(all stock), but had a 4 speed Allison trans. It felt slower accelerating to speed, but going down the highway, felt like it had as much power as the V-10. It did downshift & upshift more frequently, but that was due to a 4 speed vs. a 6 speed trans.
I have been a "GM GUY" all my life, but must admit that the V-10 has been very impressive overall. Especially the "RPM" range when using the transmission brake coming down a mountain! Inadvertantly, it was turning like 6200 til I got the damn thing slowed back down (that's another story for another day) !
All in all the Ford V-10 has become a proven engine in the RV industry.
And I would hope that the 7.3 V-8 will every bit as good, if not better!
Time will tell!
Hope this helps a bit, as it is just another perspective of the engines & their performance!