when i cloned mine i left the interior for a 72 but if you wish to change that ,the dash pad has challenger embroried so to speak on to the pad instead of a little plastic plate..the headliner is 5 bow instead of 4,,the 70 rallye gauges have the reset knobs for speedo and clock thru the woodgrain part instead of thru the clear lenses like 72 and up,,the seats have a different grain pattern as well as different seat foams on the front are different,,those are the biggest things that i know of,,and you said you bought a 70 grill,,for the headlights you need the backing plates that weld to the fenders so you can put your headlight buckets in,,and the hood release latch itself (not the safty latch) is different,,and the marker lights and holes on the sheet meatal are different