need a gear calculator
 

Guys, I am switching to a 3.73 rear gear from my current 4.10. I need a calculator to play around with the numbers.

My weight is 2800# and I cross the line at 7-7200 rpm's on motor and around 7500-7800 rpm's on 125shot.
It traps around 132-134mph on motor and 142-144mph on the 125 shot.

The problem is my car runs out of steam around 1000' and is just flat and does not pull any harder. It feels like it reaches it's peak and just stays there the last 300'.
So I think a gear change will help. It is cheaper than a bunch more motor work lol.

I found it once I got to poking around for a minute.

Does anyone know the stock th400 gear ratio for 1st and 2nd? 3rd is 1:1 but what is the other two?

2.48 and 1.48, respectively.

What size tire are you running?

http://www.wallaceracing.com/Calculators.htm

http://www.windyhollowdragway.com/horsepower2.htm