If you switch from the 4.27 to the 3.92 you only drop around 230 RPM for the same speed.
Just a heads up, I went to the link and checked the info on that R&P set. It should have more info on there than it has. The smaller ring gears were generally set up on a smaller diameter carrier by Dana Spicer. I would want to know what diameter carrier that R&P set was made to fit (bolt circle diameter). If it is the smaller carrier, you would have to purchase one from Randy's R&P since I know of no other "New" part source but they are for Dana 44 and may not work in the 41. It may be made to fit the 3.73:1 carrier that is smaller than the 4.27:1 ratio carrier in the Dana 44 but I don't know about the Dana 41. The ring gear just has to be measured for the bolt circle diameter.
I called Early Ford V8 before I ordered to make sure they would fit. They assured me that they would fit the Dana 41 with the 4.27 ratio. These guys have these made in Europe and are the only place that I know of that you can get these gears.
I don't intend the haul anything of any weight and I just wanted a low rpm at 65-70 mph.