Question, installing a 4l80e 6x 6speed auto from TCI

[dsapper]

I have near future plans to install the 6 speed auto 4l80e in my grand national after the suspension is installed. I'm installing all the SC&C goodies.

The question is this. What rear end gear ratio? I'm going with a ford 9" rear and can't pick the stock gear ratio. I've heard that the stock gears are the way to go with these cars but I'm assuming thats with the stock 4 speed automatic. What happens when we go to the six? Can I exploit those better gear ratios and go with a 3.73 or (gasp) a 4.10?

Any advice or opinions would be appriciated

ps heres the link for the transmission, its the far right tab labeled 6x
TCI® - Sorry...

 

[SSedan64]

I wouldn't think you would want to go numerically higher with the rear gear.
You can get 3.00, 3.25, 3.50, 3.55, 3.70, etc.. for a 9".

Trans-=--1st----2nd----3rd----4th----5th----6th Gear--------------------
2004R-=-2.74---1.57---1.00---0.67---------------------------------------
6X---=--2.97---2.23---1.57---1.18---1.00---0.75--------------------------

 

[CreepinDeth]

Just a consideration, Approximately two weeks left on Jake's Performance 4L80E sale - LS1TECH

 

[Reggie West]

If it were me I would stick with the stock 3.42 gears and see how that works.

A v6 cruising at 75 mph and only turning 2000 rpms might get some very good gas mileage.

 

[overkillphil]

If it were mine, with that steeper 1st gear and milder OD (albiet slightly) I'd either keep the stock gears or go numerically lower to a 3.23:1 R&P.

 

[dsapper]

well its a ford 9" so my two options are 3.25 or 3.50

 

[overkillphil]

Oops, duly noted.