47-55.1 bump steer

[nvrdone]

I've been thinking about installing power steering in my'49 using the kit that POL sells. It mounts the p/s box ahead of the axle giving more room for headers etc. Yes, I do have a dropped I beam axle
I have read comments that mounting the steering box forward of the axle causes serious bump steer, but I haven't found any info verifying this. The only reason seems to be that with the drag link going forward and the spring shackles on the forward end of the spring that causes the problem.
My understanding is that bump steer is caused if the drag link is not parallel to the ground. I cant find any info indicating that the mounting location of the spring shackles causes this problem.
I have seen class 8 big rigs with the p/s box and shackles on the front of the frame.
Can any one enlighten me on this be for I go and spend the $$$ for the kit.
Thanks