Jon please dont take this as an argument but your statement of "the best place to mount the rack is strait inline with the steering arms" is not correct as far as Mustangs go packaging wise. The available kits all struggle with varying degrees of bump steer because the tie rod ends are too short ,the engine locations limits raising the rack and the oil pan limits locating the rack farther forward. On a drag race application all the above can be lived with. On the street with just a cruiser the available kits work ok , some feel "better" but with only two high dollar exceptions all the rack and pinion kits have worse bump steer tendencies than stock Mustang steering.
Currently the "best' (IMHO) steering solution for an early Mustang is stock linkage in near new,or new,condition and a Borgesen or CPP (I think) power steering box and Saginaw pump.
Before I knew better I built a R&P set up for my 64 Comet , made a nice 2" square cross member, mounted the R&P inline with the steering arms all strait and in line , just turning at moderate speeds would cause the front tires to squeal. Just the body role changed the toe enough to mess up the steering.
I consulted with a very kind local chassis builder and moved the rack to within 1/8" of the oil pan (up) and moved it as far foreword as the oil pan sump would allow. I never measured the bump steer on that car but it was drivable for over 25,000 miles,but, it was still squirmy when topping rolling hills. It also went pigeon toed when the front end was jacked up.
