9" Torque biasing diff questions. Truetrac, Quaife

[Bentworker]

I have a 71 Grande with a stroked 351C.

Long story short I have somewhere just over 500 hp at the flywheel.

Now I am working on the rest of the drive train and I need to make some choices. The car has a 28 spline 9” rear end. The new rear end will have a nodular iron 3rd member, Daytona style pinion support and 31 spline axles, but I am still up in the air trying to decide what differential to go with. I want some sort of torque biasing differential like a Detroit Truetrac or a Quaife, but the local guy who I want to have build the rear axle seems to think they are a bad idea for that kind of horsepower, saying that I may have problems when launching (may have problems keeping it straight?). He recommends a built clutch style limited slip. Has anybody heard of such a thing? I have a torque biasing diff in my diesel pickup (390hp 730lbs torque) and I love it, I have put 43,000 miles on it and it still hooks up as good as it did the first day. As far a usage the car is just a street toy, I may take it to the autocross track for some fun, but I have no intention of drag racing on a regular basis.

I am tempted to push ahead against the guys advice (he is Bill Kingston in Redding CA), but he seems to be knowledgeable, I really don’t want to build the rear end twice.

Something else I’m wondering about is how to compare the holding ability of two different torque biasing differentials. Point being, a Quaife is $900, a Detroit is $400, and a DPI is about $700, so what is the difference?

Thanks,
Peter

 

[70vert]

that's my plan too

I'm aiming for about that amount of horsepower and a torque biasing diff. I've been reading up for a while, and the torque biasing units just seem to work correctly. The clutches would be more apt to wear out in an LSD, I'd imagine.
Don't forget Torsen either, the T2 or T2R. I am planning on the DPI Black God, 1/4 tight just in case I ever get an inside wheel up in the air. The preloaded diffs like the 1/4 tight also seem to require periodic adjustment if you are road or autocross racing, which I will rarely if ever do. It would just "wear out" to a torque biasing diff with no preload anyway, and I could rebuild it for a round of racing if I ever did that.
Corner-carvers.com has a LOT of guys running various torque sensing/biasing diffs. Except for some initial issues with Torsen units and TrueTracs breaking, these diffs seem to have a good rep . . .

 

[Sundance]

I wouldn't use it for drag racing due to shock loads. If you do intend to abuse it drag racing don't use slicks. Other wise they are good up to 700 hp. The Black Gold's are rated even higher.

I can't see shelling out that kind of doe when other options are available for a third the cost unless you compete for money.