1965 Prestolite D.P. Vacuum advance diaphragm.

I have everything ready to put my dizzy back together other than a advance diaphragm.

I am having a hard time finding the correct replacement part number, or one that is going to work as a replacement.

Can someone that has been in this spot before give me direction on my options?

Thanks FABO.
I believe this is what you need, I got mine here:

https://www.manciniracing.com/vacadvan2.html