There were two U code '70 cudas in my hometown back in 1970 according to my dad. I know that's no help now, but nevertheless...both were owned by family members.
Both automatics. One was black, black interior, black vinyl top, no hockey stripe. The other was that bronze color.

Good friend owns the one below. U code '70 Challenger w/ its original shaker. Also sold locally when new.

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CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax