You’ll need to buy a plastic film capacitor to use as a replacement because the old oil filled type had very hazardous chemicals so are no longer available.
Generally the film capacitor will be far smaller for the same capacitance and voltage rating so usually there is no problem making a replacement fit in the enclosure.
Least expensive option is a radial lead unit from TDK.
If you want an axial lead unit you’ll pay 5X the price (axial are not common anymore).
FYI the “WV” is wave voltage, aka AC rating, 400 VAC capacitors have a much higher DC rating (my examples are 630 VDC & 1000 VDC). The “outside” label indicates the lead connected to the metal casing so you know which side to connect to neutral in across the AC line applications.