https://www.clublexus.com/forums/sho...threadid=83683

Just look in there..

 

This's gonna be a hard one to do. You're trying to convert a single piston on the 90 LS to a dual piston from SC430. You will need to replace a complete knuckle assembly along with wheel bearing/ may be wheels. Plus, you'll have to considering about the suspension set up between the 90 LS and 02 SC430, so forget about this project.

 

Maybe that's the part name I was looking for. the knuckle? I guess it's longer on the SC's.

Some other people suggessted the 1995 LS brakes. These are also 2 piston.

1993 might be my only chance to try and fit.

 

The 95 LS has 4 pistons set up. Like you said, the only choice you got is the 93-94 LS set up because of the similarity on the front suspension. Let us know how it turn out.