I have an 87 5th Ave 318 with stock 2.20 rear gear. It runs cool.
It "was" very nice at 80 mph, but a real dog in town. As in the most aggravating car I've ever driven. Worse than an old 36 hp VW beetle. Really, I'm serious.
So, I moved the shift points up 15 mph, just fine in town now.
Leaves...