A nickel fits into any EGR fitting but it's not a great plug 'cause something has to hold it in. As I said, the ASP budget header does not have an EGR fitting -- only O2 sensor fittings. If you want to plug an O2 sensor fitting, use an old O2 sensor or buy a plug to fit an O2 sensor bung. Use Google and you will find lots of sources for O2 sensor bungs and plugs.