Here are some I have used in my transistorized ignition, which condensers have the same specs as the condensers in the conventional ignition set up. I have the yellow now (630V), the green one is also 630V, which I have bought a couple of for € 1,- each in a dumpstore. The blue one I have used for 20 years, is now still serving in a module I made for a friend. The latter is 400V, which has proved big enough. So maybe you can find some of the green ones. Brand and type are visible in the pic.
Those green ones look like the polystyrene type? If so, check on their operating temperature: I once made an Ignition for a truck's engine with one of those, but after about 1 years' heavy use the case of the capacitor warped and I had to change it. I used ceramic the next time. It was very hot under this hood: the truck often idled all day on worksites.
I myself have never measured the temperature at the ignition plate, but a range of -55 °C to +100 °C is good enough for where I have mounted mine (see pic) and also for near the coils. I have chosen that particular spot for my module as the battery is somewhat cushioned. The reason OEM regulators seem to live forever is because Honda took good care to cushion it. The Bosch regulator on my yacht was
not and fell completely apart, be it after 30 years.
The condenser in the pic was even less than 1 euro and I bought a couple at a electronics dumpstore a ten minute walk from where I live.
