well i have been looking around to find the tallest gear ratio available for an sc400. looking to drop in a 550-600whp LS/t56 combo and im looking to get in the 2.73 gear range. this will be more of a top speed specific car. are ring gears available in this size? or close to? which leads me to my next question, how much HP realistically can the diff hold? a ford 9" section custom fabbed would be an idea, but i have not seen any info on this, so im assuming there must be a lexus diff that can hold power with some mods. any info is appreciated. thank you

 

I believe the TT TRD rear diff is a 3.27. Not quite what you're looking for but basically a bolt-on. There are two, a 10 bolt and a 12 bolt. You'll need a 10 bolt to fit the SC housing. Not sure if there's a variance in ratio between the 10 bolt and 12 bolt.

If you have the funds or the means to do a complete Ford 9", the TT swap is perfect for you. The one in my friend's car has held up to over 1100 horsepower and over 900 torque from a roll or dig, it takes is all.

 

The gearing has really nothing to do with the TRD Diff.. The TRD diff is a true limited slip with clutch packs and beefier spider gears inside to wistand the abuse of high powered cars..

The tallest gearing would be 3.13 which is the USDM TT 6 Speed diff..

 

^, I know.

I was suggesting the TRD diff over the Ford 9" in terms of holding the power and torque, not because of it's gearing.

 

I wanna put a 503 ring gear in my sc400. I wanna burn more rubber