The discussion about the change from cad-zinc 5/8" ATF hex nuts (GM 124573) to black phos 11/16" hex nuts (GM 9418897) for the majority of front and rear bumper nuts is in this thread:
It looks like the same discussion applies to the No. 1 body mount nuts (1967 AIM, 1ASM-G1 coupe and 1ASM-G3 convertible). The 1963-1966 AIMs show the No. 1 body mount nut was the GM 124573 zinc-cad 5/8" ATF hex nut. The 67 AIM Revision Record shows that it WAS GM 124573 but changed to GM 9418897, dated 10-27-66.
For those of you with '67s that still have your original No. 1 body mount bolts/nuts, what is your build date and do you have the zinc-cad 5/8" wrench-size hex nuts or the black phosphate 11/16" wrench-size hex nuts?
It looks like the same discussion applies to the No. 1 body mount nuts (1967 AIM, 1ASM-G1 coupe and 1ASM-G3 convertible). The 1963-1966 AIMs show the No. 1 body mount nut was the GM 124573 zinc-cad 5/8" ATF hex nut. The 67 AIM Revision Record shows that it WAS GM 124573 but changed to GM 9418897, dated 10-27-66.
For those of you with '67s that still have your original No. 1 body mount bolts/nuts, what is your build date and do you have the zinc-cad 5/8" wrench-size hex nuts or the black phosphate 11/16" wrench-size hex nuts?