Brake booster rubber boot/bellows

[StingRay]

A couple of brake boosters I have need the rubber boot or bellows on the input side push rod replaced and for the life of me I can't find any info on brake boosters anywhere. The two I have are the Delco units from 72 that have the gold/silver plating and the plastic deally sticking out the back that the boot covers over. The older boosters (69-70) that are not plated but rather in black paint don't seem to ever need a new boot and it is different than the newer 72 type units use anyway. Does anybody know where to find these elusive rubber parts? I have also noticed that there must be a foam rubber part that wraps around the pushrod as well. These are disintegrating and will need replacing as well. Any help is appreciated.