I went from a 1:76 to a 1:80 and didn't notice anything different? If you figure his final drive ratio it's 8.55 with the 1:76 and 8.78 with the 1:80?
I ran a 2250 lb door car with a 406 SBC, 33 inch tire and a 5:57 and it still wasn't low enough for eight mile tracks. Actually ran some quarter miles with that thing but was into the 7200 chip before the finish line!
What RPM is it shifted at and how much converter is in it?