Hrrm, jmo have you driven it yet? with that kinda hp are you planning on winding the hell out of it in the quarter or running 1/8 only? May not need a ton of gear in the first place. Especially with a high end converter and a light car.

I have a us gear unit for a 4l80e I got for a song, it looks as if it has a pair of limit switches and the motor. I am planning on some transistors and/or relays to control it as I did not get the box.

Ps:2000 bucks buys a lotta gas!

 

Yup, I drive it all the time. I went from 3.27's to 2.73's in rear. I might go to a 3.08 eventually and just let it be done. I'm not as worried about the gas mileage as I am just turning the higher RPM all the time, wear and tear on things that normally on the highway it would be easier on. But I guess it's like anything. Unfortunately I don't have a big budget so there will be sacrifice somewhere.

 

Honestly, at 70mph you'll be at 2300 RPM with a 3 spd, the fourth gear will put it at 1600. About a 700 RPM difference before the converter slip. At 85mph that becomes around a 900 RPM difference. I'd be leaning towards making sure you have the best converter in it possible so that you don't slip too much under cruising loads. It's really a shame they don't make a lock up kit for the 400s in a way. Then again if they did it'd probably use the 80E converter which is one of the big expenses with the whole mess anyways.

 

I know there was someone making a lockup kit for the TH400's but I have a feeling it'll be more then it's worth unfortunately.

 

You are going to try to hook 1000hp with a 3.55 and a 2.48 first gear? You will have to pull power with your cuttent set up and you want more ratio?

 

With 28" slicks I don't see a problem... although I haven't even had a chance to test it with the 2.73's yet either... I guess I could always go down in tire size as well for more "gear" if needed.