Large O ring on dizzy? Rubber or other
A member I think here did a great thread on different fuses and when they they actually blew, some were way out of specs, really scarry.
That thread is
here. Also see
here.
Halifaxshops, it's probably staring me in the face, but what are you asking me to notice about one or the other distributor in your pic, aside from one having and one not having the large O-ring?
Anyhow:
Chrysler P/N for the top O-ring is 2095 740, discontinued, and the inner diameter is 1.068". Buna-N is an acceptable material. Find it around as a "size 121 round O-ring", such as
here (a hundred of them for under ten bucks) or
here (one for 35¢, but shipping will probably make it more worthwhile getting the 100-pack, then when the end of the world comes you'll be prepared).
Chrysler P/N for the bottom O-ring is 2095 630, discontinued, and the inner diameter is 0.920". I'm pretty sure it's a size 021 square O-ring such as
this (where you can also read about Buna-N material's characteristics), though it's been long enough since I scrutinized one of these that my recollection of them as square-section could be wrong—they might well start out as round and the outer diameter gets squished flat with pressure, heat, and time. Also possible it's an 020-size ring (outer diameter 1.004") or an 022-size ring (outer diameter 1.129").
These size numbers apply whether you're getting round- or square-section O-rings, so google searches are easy.