Father-Son 1974 Duster Project
Drill the radiator out to 1/4" and buy "u" nuts from NAPA for $5 a pack.
I just bought the nuts last week "trying" to fit a factory shroud on a aluminum radiator.
The bolt holes aligned, but the shroud was too big to clear the radiator necks.
I could trim the factory shroud, but it would be easier to find a correct brass radiator.