I’m pretty certain all gbody rear upper and lowers have the same size bolts. As a matter of fact, when I put some 2000 Camaro rear LCAs on my 81 Malibu , I used the fbody bolts because they looked brand new.
When it comes to bolts and fasteners, I always prefer the factory ones. I just removed the body off on my 82 bonneville . Broke three bolts that were rusted . I looked at bolt kits and they didn’t look that good and were expensive when really I just needed three bolts. I hit the junkyards and got about twelve of them . They were rust free and still had the black factory color. I found the number fours were usually the best ones. I just reached under with my impact and zipped them out.
B body’s use the same bolts. The best part is they didn’t even charge me for the bolts.
All three broke bolts are in the trunk. I plan on cutting from above and use a nut and washer. To find the factory nut , I found that the nut that attaches the steering shaft to the column is the right size. It is a flanged nut and will work great. Once I get it bolted back together , I’ll fold the flaps I cut in the trunk and weld them back..
timo22