Looking for some Differential advice

With 3.73s and 26s, 80mph maths to about 4000 at 5% slip, just saying. I sure wouldn't run my slanty far at that rpm; my stockers usually threw a rod out the side shortly after that.
I would consider that situation as close to impossible as is possible, without actually being impossible; possibly being just, nearly impossible; while quite possibly being dangerously close to a possible engine-failure.
I might possibly be wrong, but in this case I doubt that's possible; yet I admit that there is an ever so small and slight possibility.
Now, having said that, consider that it is possible that we Earthlings do not actually live on a ball, but very possibly .........