Over the winter,my 3.31's will be going in,and I'm seriously considering going to a 2.75 1st gear (2.48 is stock) in my TH400
Might be fun at the track with a pair of ET streets smile.gif

My 1st gear will be the same as a stock 2.48 geared TH400 with 3.73's
I really like the idea of cruiser friendly 3.31's and not having steep gears or an overdrive trans.
Just an FYI guys

Hey Chris,

As you know, the mechanical advantage of the 2.75 would help in 60 ft. But what I was thinking that the drop between 1st and 2nd may lug the motor since you do not have a real loose converter if my memory serves me correct.

I am in first gear less than 2 seconds just past the 60 ft mark with the 2.48. It would be at or just before the 60 ft mark with the 2.75 gear

I am interested what some of the replies from those that have done this will be. Funny I was considering this myself on and off last season.

Originally posted by mr 4 speed:
Over the winter,my 3.31's will be going in,and I'm seriously considering going to a 2.75 1st gear (2.48 is stock) in my TH400
Might be fun at the track with a pair of ET streets smile.gif

My 1st gear will be the same as a stock 2.48 geared TH400 with 3.73's
I really like the idea of cruiser friendly 3.31's and not having steep gears or an overdrive trans.
Just an FYI guys Chris,

I think it's a great idea. I plan to do the same to mine the very next time it's out for a freshen up (which hopefully won't be for a while). According to my rough calculations you could expect a 25% increase in torque at the ground. Your current 1st gear ratio is 6.77 and the new one will be 9.10. Assuming 450 ft lbs the torque at the axles will go from 3,046 ft lbs to 4,095 ft lbs. Slicks will difinitely be a requirement and I would expect to see a gain of .25 or better in 60' assuming you could get a bite. Of course you will need to update your web site:

Future Accomplishment: I refuse to gear this car-I want to see what the "outer limits" of 2.73's are ET wise!!tongue.gif

I used to have a list of "refuse to do" upgrades for my car which included:

- no weight reduction
- no roll bar
- no automatic
- no deep gears
- no battery relocation
- all steel
- no trailer
- pump gas

I managed to run a best of 11.87@116+ will "sticking" to my guns. However in the past two years all of that has changed smile.gif

Asop's Fable? Never say never! ;)

Thanks for the input guys.Tom,I am wondering too about the 1-2 gear drop.As long as I focus on traction and the corresponding 60 ft. improvements,I'm hoping my goals of 12.7X's or so (high 12.6X would be nice ;) ) I'd be more than satisfied,and if its any quicke,well thats just a bonus.With 26" tall slicks,I would be crossing the stripe a hair below 5000 RPM's (with a 5500 shift point) with the 3.31's,which is what I want.
I have a minimalistic goal for this car,which has been met already(12.99),and being able to continue the same theme for a few more tenths seems reasonable.Focusing on an aggressive 60 ft. is all I need to see those improvements.

Hmm...I was thinking of swapping out my th400's 2.48 gear set with a 2.10 low set. It's still a possibility in the future if traction becomes an issue with the DR's and a higher powered engine down the road.