There are programs to calculate steering and front suspension locations. The problem can be getting an accurate measurements of the existing car. Have a look at some oval track racing sites.

Rack inner tie rod end center to center is important, matching body length to existing tie rod center won't work.

Ackerman is "toe out on turns" ( outside wheel needs a larger turning radius than the inner wheel ) and is only affected by the angle of the steering arms at the spindles, it won't change by changing the rack.