Looking for a 2.73 ratio rear end for Malibu

[Rotech]

Thanks for your input guys. Let's see what I find at the yard.

 

[oldsmobile joe]

check out the full size cars from the late seventies and early eighties with three speed auto. some came with that gear ratio.

 

[Rotech]

Hey guys, I found a Torsen posi with a 3.23 you think this is a good choice ?

 

[UNGN]

You will like 3.23's over 2.73's and a Torsen is great for handling... not the best for slicks at a drag strip, but for driving around corners, its hard to beat.

 

[Texas82GP]

Tell us more about your car. What engine, trans, tire size, mods....

 

[Rotech]

I am building towards a motor , but still not decided how big yet. I just changed a th200 for a th2004R. I have 15 inch wheels currently the car has a 6 cylinder. plans for my malibu is street use but with power under the hood. I stumbled on a used torsen with 3,23 for $200. looks like a good deal. what do you think ?

 

[oldsmobile joe]

Good purchase. that's what called a 3 series, 3.23 to 4.10 gears fit on that unit. a 2 series fits 2.29 up to 3.08. with a 2004r trans, that is a great place to start.

 

[Texas82GP]

I am building towards a motor , but still not decided how big yet. I just changed a th200 for a th2004R. I have 15 inch wheels currently the car has a 6 cylinder. plans for my malibu is street use but with power under the hood. I stumbled on a used torsen with 3,23 for $200. looks like a good deal. what do you think ?

The diff itself is a good buy. I would swap to a 3.42 or perhaps even a 3.73 gear set. It depends on tire height. Assuming a 26" rear tire (235/60/15) and the 0.67 overdrive ratio of the 200-4R, a 3.73 would put you at 2574 RPM at 80 mph which is good. Also the 2.74 first gear in the 200-4R x 3.73 gives a 10.2 final drive ratio in 1st gear which is a little steep but still good. The car would be quite spunky with the 3.73.

 

[Rotech]

How would that affect long range driving on the motor with a 3.73?

 

[Texas82GP]

With the overdrive the motor won't race at highway speed with the 3.73. That's the beauty of the overdrive. 2600 RPM at 80mph is just about right. With the same assumed tire size (26"), at 70mph it will turn 2100 RPM. At 50mph it will turn 1615 rpm in overdrive.
http://www.csgnetwork.com/multirpmcalc.html