Radiator Cap Catalog?

I work on equipment of various types and ages. One thing that is common is radiator caps getting rotten.

All the catalogs want you to look it up by year, make, model, number of miles and paint color. Well none of my generators are listed.

We use small Japanese caps, regular automotive like an old pickup, and large ones like heavy trucks used to commonly have and many still do.

But I need some way to look them up by pressure, sometimes dimensions, and features such as sealing ring for...

Radiator Cap Catalog?

Radiator Cap Catalog?