Steering rack selection

[astroracer]

Swapping to a rack involves a whole lot more thought than most people realize. That's why this question gets asked so often. Swapping a rack (pick a rack, any rack) into a suspension that was not initially designed with that intent usually creates a suspension with unusual amounts of bumpsteer and drastically reduced (or increased) turn radii. The racks inner tierod pivot point locations are tied directly into the upper and lower control arm pivot points. If the inner tierod points aren't in the right location (both cross-car, longitudinally AND vertically) this will cause all kinds of issues with bumpsteer, road feel, turn-in and turn-out.
Read this Longacre article. Best explanation I have found of why NOT to try to adapt a rack where it doesn't belong....
http://www.longacreracing.com/articles/art.asp?ARTID=13
Like it says in the article, to do this right you need to start with a clean sheet of paper and design the suspension (read that suspension AND frame) AROUND the rack.