A lonnnggg time ago (about 1977), I made the conversion from my '72... bought a new 70 grille, bought a new full tail light panel... cut out the fender side-light areas and welded in same from junk yard fenders (essentially changing my fenders to become 70-71 fenders.
Took off the Rally front fender side pieces and strobe stripes, welded the holes.. Welded the antenna front fender whole; relocated to correct r/r quarter panel area. Installed the different wiring harnesses for the lighting. Repainted accordingly and added the T/A stripes (actually, perfectly painted on using a T/A for dimensions (the sided mirrors are located differently on 70-71 vs 72-74 doors, so the factory decal striping wouldn't match correctly.
Some items new, some from cars stripping for parts (T/As and AARs).
I owe it all to my best friend who owns a body shop and is Mopar guy and perfectionist in all his work.
All this was done simply for SCCA Solo II AX rules, at that time.... later years... they changed the rules whereby I wouldn't have had to do this to the car.... was a nice rust-free 318 '72 Rally... now 340-6 T/A... clone/tribute... and I've continued to race it a lot for AX/HSAX/HPDE events.... won multiple season championships since the late 70's. Enjoying the car as a '70 T/A in all my campaigns... races and shows.