Appreciate the information as I've been contemplating the swap. Maybe some other Bolters will share their experience?
Dusty -- For awhile, I ran the 216/4.10/4-speed SM420/17-inch wheel combo on my 3804. My truck could maintain 70-ish on a flat just fine (but you could tell that was all there was

) but as soon as I hit a headwind (or even much of a breeze, let alone wind) or any kind of a hill, it went to 55. A real hill meant dropping a gear. or two ... Not really a show stopper, just more of a slight annoyance at times. And in the back of my mind, I was always worried about what running at the upper right corner of the "Horsepower/thrust Curve" was doing to my valiant splasher 216...
Then I switched to a 261 and ... well, I no longer have these issues

And the still-good 216 is sleeping peacefully in the corner... for now ...
Just my data point FWIW.
John