Convert 420 SEC to 500 SEC?

Hello everyone! Since my 500s is accident, I would like to bring them back to life or at least put them in a new skin. It connects me a lot with her.Therefore I ask it is possible to convert the components of my 500 SEC BJ1991 with ASR into a 420 SEC from the BJ 1986? Does the Euro D3 stay with me then, or does it go with such flutes? Is there then problems because of the ASR? does the 420er have the same differential? How is this with the starting moment support? Is it? t this retrofittable/refitable? Please advise me on expert advice! MfG vl