I think would work for '68-70 as well - In this thread Duane describes the differences: https://v8buick.com/index.php?threads/rear-frame-section-68-72.381879/#post-3349050 Seems to be very solid. The two center body mount locations should be repaired. Unfortunately this was from a parts car the PO had & I guess "the girls" who were "restoring" my convertible couldn't get the rear body bolts out and cut the back of the frame off instead of cutting the body they junked. Pretty easy repair and a couple ways to do it depending on the desired results/usage: Either just add back the missing part (cut/splice/butt weld &/or add a plate to join) or cut at the seam & replace the whole back section (that’s what I'd do - Seam shown in red in one of the pics). If you need a frame & the back section of yours is useable, this is a great opportunity here to get into a good frame for reasonable $. I can check anything specific or take any other pics but it really seems to be quite a solid piece. As-Is: $450 With back section included, but not installed: $650 With back section installed (@seams) & body mount locations repaired: $1500. Pick up near Baltimore, MD.
If I can get at the ugly pair I have,I can show you where they usually go bad first. If you look at where it joins the front,just back from where the e-brake cable passes through. They can get weird at those front spots.
