I want to put a Torsen type limited slip carrier in my 10-bolt - pic attached. The rear in my '72 cutlass is coded SA which is I think is a corporate 2.73; I want to change to a 3.42 to better work with a 200-4r OD trans. I'm building a DD and would like to run synthetic fluid for MPG (synthetic won't work with a stock posi???) Is the Detroit True-Trac a torsen? Can I run synthetic oil with a Torsen? Do the torsens have better manners on wet roads? It rains a lot here in Houston!

 

-yES SYNTHETIC IS FINE FOR THE WORM GEAR POSI UNITS
-Yes 3.42 will be better with the overdrive even 3.73 might be better depending on the tire size and camshaft profile.
-True trac/ torsen posi unit accel in the curves and wet etc. They have very good manners and bias the power very well in the turns.
I have a true trac on the shelf if you need a price quote shot an emailo over and we have gears rebuild kit etc. Then you have a base line for price checking around. Jim
You have a 10 bolt 8.5 Cutlass rear - 28 spline axles Bolt in Axles

HAVE A FUN HOLIDAY SEASON!

 

Jim:
I'll shoot you a PM to get some pricing. Will there be more drive-line loses running a torsen vs. a clutch-type posi? It seems like there are a lot more moving parts and gears in the torsen that would eat up some HP on the way to the rear wheels. I plan on running a stock stall convertor (1700rpm) without the lock-up and rear tires will be 26.7"-27" diameter. I crunched some numbers with a 3.42 rear gear and the final ratio would be 2.29 and the first gear ratio would be 9.37. Seems like a win-win here, almost 10:1 first gear should give good acceleration and the 2.29:1 final will keep the engine speed around 2000 RPM at 70MPH for decent cruising MPG. Thanks!
Rodney