If it is earlier than the (stinking) crimped style, which were not intended to be serviceable, they may be had from these folks:
http://www.maritimedragracing.com/then_and_now_automotive.htm I have bought from them and the part quality was superb. I highly recommend them. The kits are alcohol resistant and the valve inserts are built to last. They will want to know the list number. On yours it is probably stamped into the edge of the mounting flange. My guess is that you have an AC 4206 fuel pump. If so, you need kit #FPA-228. My last purchase of this kit was $69.50 + $8.50 shipping. It is possible to mount a glass bowl on the newer "all metal" version of the AC 4206.
Mating up the diaphragms isn't so hard. The one just hooks on and the other starts 90 degrees rotated from the final position and is then spun to the right orientation to lock it into place.
These kits do come with instructions that are pretty good but be sure to write notes or take pictures so that you replace each valve in the right orientation. Once they go in, they won't come back out without a fight!