Bilstein HD inserts, #34-000243, don't fit my '74 CS coupe. NOt only will they not fully insert into the strut, the threaded collar ring is too big. Given their apparent wide-spread use,WTF? Anybody had these problems? Maybe I have struts from an E3 or E12 or something. At this point I think I'll have no choice but to replace the KYBs I pulled out. Help.