So, is this a bad idea?

I was over at the transmission calculator site. I was thinking of keeping the 4-speed since I really enjoy it. Checking out the different differential ratios, seems like a new diff might be on its way out, or the 4-speed.

Anyone with a 4-speed and higher diff ratio then stock? Looking at it, the 3.54 diff seems pretty much the same as the 3.36, just a minor difference. Still pretty much 3,000rpm at 65mph, but once you get to 3.7 and higher, things seem to start going out the window. 3,000rpm = 60mph w/ 3.7. Mostly concerned of top gear RPM count at higher speeds and it just seems like everything went out the window.

Acceleration sure does look quiet nice looking at it, but the RPM count in 4th gear at speeds of 60 and higher seem to just be way too high for my likings. Don't travel often on the interstate, but when I do, I like to go at least a minimum of 65mph.

Was hoping to stay 4-Speed w/ new diff. So maybe only a 3.54 diff if I stick with the 4-speed, 3.7 diff tops?

The 3.70 was usually mated with a 5 speed except in the 810 as some of them had four speeds. I have a 3.70 in my 810 and the highway RPM is fine...once you shift to 5th. Don't think I'd like the 3.70 with a 4 speed. Not even sure I'd care much for the 3.545 with a 4 speed.