Changing Rear End Gears

[BUICKTR]

I know there are alot of people with the stock 3.42 gears. My question will our cars benefit from a 3.73 or 3.90 if it is more race application than street. For example, my car is just a weekend warrior and track. I run a modify 2004-R with a 9" conv (3200) stall. I do run 28x10.5x15 on Weld Drag Stars.

 

[buickboy]

GM did their homework on the gear ratio choice for the Corporate 10 bolt. Stay with the 3:42's it is the best all around gearing street/strip
Mitch

 

[UNGN]

Not without ported heads and a cam. Even then you can be fast enough to run out of breath in the 1/4.

How fast do you want to run in the 1/4?. The faster you go, the less gear you'll want. For 10's in the mid 120's, it's hard to beat 3.42 gears.

 

[BUICKTR]

Thanks!! My goal is to run a mid 10 at around 125-127 mph This is probably all I'm going to want out of my Buick. It already has ran a 11.38 at 121 mph and it already scares me.

 

[SPECTRA PREMIUM]

I have tried 3.08, 3.70 , 4.56 and I went back to the 3.42's
don't change them....

Joe

 

[Gary]

If you are running a 28" tall tire, you are no longer running 3.42 gearing. The taller tire has reduced your gearing to about 3.08. If you insatll 3.73 gears with a 28"tall tire you will then be geared 3.46. The object here is to increase traction by creating a larger diameter tire while keeping the near stock gearing. 28" tall tire and 3.73 gears is an excellent setup for racing the Turbo Buick. I've used this set up on four different cars.

Gary

 

[TurboShane]

I thought part of the goal of adding taller tires was to reduce RPM's going through the traps.

 

[U1ARUNIT]

Originally posted by TurboShane
I thought part of the goal of adding taller tires was to reduce RPM's going through the traps.

Yes, that and to increase the contact patch for more traction.