200R4

[LJC]

I found a 200R4. having it rebuilt, my question is should I switch out the rear end it is currently stock but was considering posi. and different gear ratio?

 

[Bob]

If you are putting in an older Buick, you have no choice, if it has a torque tube. If it is new enough to have an open driveshaft, then it is your preference.

 

[LJC]

I'm swapping out the TH350 that is in it

 

[LJC]

adding a new converter as well

 

[Dr. Frankenbuick]

What is the current ratio?


Sent from my iPhone using Tapatalk

 

[LJC]

That I'm not sure of I would have to " Ass Out of U and Me " that it is stock from the original switch pitch

 

[LJC]

Have a couple of months till spring so I have time to replace it

 

[Dr. Frankenbuick]

Talking about rear end ratio?


Sent from my iPhone using Tapatalk

 

[LARRY70GS]

That I'm not sure of I would have to " Ass Out of U and Me " that it is stock from the original switch pitch

Might help if we knew what year and model the car is. If it has an original switch pitch, then it is a 65-67. Might be a 2.93. If you don't want to ASS-U-ME, you could jack the car up and mark the tire and driveshaft, then rotate the tire one revolution while counting the driveshaft revolutions. Or, you could look for the axle code on the axle tubes, or if you have a tachometer, it will turn between 23 and 2400 @ 60 MPH with a 2.93.

In any case, the 2004R has a .67 overdrive 4th gear and a lock up torque converter. It will like a 3.42 rear gear so that final drive will be 3.42 X .67 = 2.29. The 2004R 1st gear of 2.74 will give you a starting ratio of 2.74 X 3.42 = 9.37