We did a TRZ rack install on a GN a couple years ago and went through the frame with the steering shaft as shown in the pic below.
After this I decided to just do my race car with a S-10 manual box, Baer brakes and G-body arms which saved me about 100 pounds and still have excellent steering.
View attachment 150095
I really do not like the idea of cutting hole in frame or losing frame braces. I am not sure how much it weakens the frame or if it is an issue but it has to weaken it.
Michael