And go at least 600v. They are paper caps in a metal can and sealed in with epoxy or resin. The metal can has two purposes, to sheild it from heat and to use the can as one of the terminals.

Automotive electrical parts usually have a very wide tolerance level, often 50% or more. So, a .33 cap would probably work. But remember it will be in a high heat, high vibration environment.

Do you use an alternator?