hardbody fuel cell install

im currently redoing a hardbody and the customer is wanting to put a fuel cell in instead of the stock tank what is required for california smog to pass? im thinkin just adapt his original fuel sender into the tank and make a filler so the factory gas cap can be used if anyone has more info please chime in thanks...

dont know about cali but florida's realy wasnt crap lol

i just did a fuel cell in my h body works great