I got replacement diaphrams from
www.autoluxmbz.com and they are the exact replacement for the original on my '84SD.
I know what you mean about that center pod being a bear. I used stainless steel safety wire (a light but strong wire) and a rod (possibly an old screwdriver) with a hole drilled in it large enough to feed two strands of the wire through. Cut about a 12-18" length of the wire, loop it around the pod and insert the ends through the hole. Pull the wire back along the rod and then twist the rod to snug the wire around the pod to the point where it will release the clips.
Of course, it always helps to hold your mouth just right.
