I'm not sure I follow you completely.
However to fit Sigma LCAs you can use AE86 rack ends, RA40 tie rod tubes and RA40 tie rod ends. You keep the AE86 (or KE70 by the looks of it) rack.
RA60 rack ends are about 20mm longer overall than AE86 rack ends. So you *may* be able to use RA60 rack ends and normal AE86 tie rods. I've never tried.
Also I'd be hesitant to use rack ends or tie rods from a wrecker. You can get them around $25-30 each from Repco/Bursons so they're worth replacing.
Hen