What springs did you use? That front is designed for GM Metric = 78/84 Chevelle pieces.
Looking at this old thread
http://67-72chevytrucks.com/vboard/s...d.php?t=670981 My memory is trying to tell me that you did not set the crossmember in the frame the way Scott designed it to be but set it up to run at stock ride height or close to it and I believe that is where your problem lies along with believing that he designed the front end to run bags and not springs. You are probably the only person who is trying to sun springs rather than bags on that front end and set it up to run at a stock ride height rather than lay frame.
He also designed it to use the 95 T bird rack that was a pretty straight forward install.
This frame is in Australia but the Jag XJ install is set at real close to stock ride height for an AD truck plus he didn't do much if any trimming on the Jag crossmember and just built brackets to connect with the stock Jag subframe straight out of the Jag. I just found the photo on FB last week.