69 dart suspension set up HELP

Rack and pinion, in and of itself, does not automatically equate to better handling. It DOES simplify the steering linkage WHEN PROPERLY DESIGNED, but there have been a few people "roll their own" who later darn near "rolled their car." Things like bump steer, tie rod linkage that is simply not strong enough, and vastly reduced turning radius are a few.

There are companies, like "Firm Feel" who can build you a high ratio manual or power box and improve the operation of power steering.

If you have LOTS of money, you can buy aftermarket front K members like Altercation.