Not exactly the same but I ran a Ramjet to a Ranger OD box to a H42 to a split case. In an FJ60 and I ran it hard. The H42 and split case was fine. H55 seen plenty of v8 and 4BT work as well.
I think you will be fine as long as you don’t try and drive it like a race car all the time. It might eat clutches faster than normal if you are hard on it as well.
Are you going to want to run it down the highway at 75+mph?
Not 75+ for sure. I feel comfortable up to around 70 in my 40 now and that is limited by the suspension and wheelbase. I'm turning about 2600RPM at 70, so I could benefit from more OD, but no more than I'll be cruising at that speed I still think that's comfortable enough. I also don't want to shop around for a used Ranger box for months, waiting to move forward with my swap.