You can keep the grill shell, but you are gonna have to modify the shell for mounting brackets. But you are gonna need factory everything. The only thing that you can get by with thats not, is a Chrysler Lebaron flip headlight modulers and canister assembly, with a lil modifiction they work faster, they flip in sync with each other and they are dependable. For what its worth, I hope that helped.
I've done a couple of conversions and it can be done. The mod is fairly significant. You're going to need a complete hidden headlight donor car. You then need to pull the front bumpers and swap absolutely everything on the back side of the bumpers: all the brackets are different - even the bumper mounting brackets. You then need to swap over the vacuum harness, reservoir, and the dash switch along with the firewall vacuum harness grommet. A few parts are available as re-pops, but not enough to do a conversion, so you'll need a donor car to pull it off.