Your new wilwood setup will have two ports for the Front and 1 port for the rear coming out of the proportioning valve. They accept your current brake line fittings and it is optional to use both front ports or just one and cap the other. In summary for you to change nothing, Cap one front port(FO) on the new wilwood master connect your current single brake line from the front to the non capped (FO) port. Connect your current rear brake line to the rear port on the wilwood prop valve(RO)
Check out the pic below might help.
https://photos.app.goo.gl/6xhx3UXAA8tjbSPNA