i am restoreing a 1976-1977 dusters can i get some help?

Hi i need to know what is going to be best for my dusters
i am restoreing a 1976 ragtop and a 1977 hardtop and i need to know what the best parts are i want to do a 340 440 hemi with a turbo kit
and i want the and i was wondering if i could change the ragtop to a hardtop
and i want you to know that these have all orig parts i belive the 1976 already has a 340 and it runs (but the last time the guy checked was six years ago) so if i could get some help that would be awesome thanks