I checked mine this morning and I was at about 2500 at 80mph. But I was driving on the freeway trying to watch the speedo and RPM's without driving into anyone so it could be off a little.
Kind of hard to tell because there has been tranny swaps and gear swaps from Ford within a few years of each other. I think the 99-01 1/2 are different from the 02s, also the 04s.
I have an 02GT and my fiance has an 04GT. Our 1st and 5th gear ratios are different. That's just a 2 year difference. No telling how many changes were made the previous years.
Just use your onboard digital tachometer. It's a little more accurate than they needle one. But I think that feature is only on the 99-04
I thought they changed the 5th gear for better fuel economy. I didn't think the gears were the same for the T45 & 3650. The gearing was changed somewhere after the 01 1/2. But the hell if I know, I read it somewhere.