I mocked up the rear first, bolted in the 4-link suspension, put the rear end, 69 Camaro 10 bolt in. Then I played with my measurements on the IFS. Made my markings, then took everything off, put the frame on blocks with the same height and tack welded the ifs in. Put everything back on the frame and checked everything out before final welding! That's how I did it. It worked for me. Check out the photos on my site, not many of the frame, but you can see our ride height and the centering of our wheels in the fender openings. I am sure others have done it differently, but it worked for me!
Coach Frank

https://sites.google.com/site/bluejaygarage/home
53 half ton http://s159.photobucket.com/user/sworden73/library/?sort=3&start=all&page=1
72 Nova SS sold
75 Corvette
52 Chevy Styleline Coupe