Gears and rears
 

So, I am looking to upgrade the rear in my car...

What should I do as far as gearing goes?

Milage on the highway doenst bother me., too much if at all

Currently har has 3.73's and does fine.

Car has a 3500 stall and currently on a 26" tall tire, would a 4.10 gear be too much where I am hitting the limiter at the track, or I would be going into 4th gear? 6400 rev limitter

You are looking at 121mph in 3rd gear (A4 car, right?) with the 4.10s. Also, you would be turning 2800 RPM @ 75mph in overdrive.

The current 3.73s would allow you to run to 133mph in 3rd gear.

This is assuming a radial tire. If you're running a bias ply you can assume some growth, and you'll have a few more mph to play with on the top end.

- Justin

did you factor in converter slip?

Yes, an auto car... its a 3500 stall currently...

Or would I be better suited going to a gear such as 3.90?

I would stay with 3.73 if you are planning to keep running the 26" tire

What might I gain from going to a 28" tire and 4.11 gears?

Even if you went with 28" tires I still dont think I would use a 4.11. Maybe more like a 3.90.
You would gain traction going to a bigger tire.