I wont go into the myriad of sheetmetal & bracket differences between '70 & '71, which include fenders, inner fenders, hood, valances, brackets, floor pan etc.

Other unique '70 items:

- console
- instruments (both rallye and regular -- there are a staggering number of unique-to-'70 Challenger parts)
- deluxe seat belts
- partial horn ring steering wheel
- gas tank vented to the atmosphere (except N95 cars)
- '70 cloth/vinyl seats are a one year only pattern
- Burnt Orange interior
- T5 tan interior (gave way to light tan & and brown options for '71)

And then into little stuff like wiring, brushed nickel vs. chrome turn signal stalks, entire dashpad and surrounding trim, front bumper fillers & accessory brackets etc...