I currently have a 2.75 first gear in my TH400, but the guy who is going to be doing my rebuild told me I should go with a 2.50 first gear.

What I'm wanting to know is if this change is going to negatively effect my 1/4 mile ET's. Obviously, the car wont launch quite has hard off the line, but it will also be in 1st gear longer.

If there will be no real difference I would assume the 2.50, so the car will launch a little easier when I put the full nitrous shot on it.

Thanks,
Jason

 

This is probably a good "Driveline" topic. The trans gurus hang out there.

The 2.75 must be an aftermarket gearset, right? If it needs replacement it's probably expensive. Stock was 2.48, I believe.
Wasn't the 350 2.50 first?

You'll see about 5 mph more in first as you said. If traction is any problem now (2.75s), it might help until you squeeze the juice to it.

My guess is 2.48s might be stronger unless 2.75s were premium material.


My $.02

 

Transfering to the Drivetrain Forum.