What bore size wilwood master cylinder

[stripe74au]

Hey all, I am looking to get a Wilwood master cylinder but just need some help determining which bore size would best suit my application.

68 Charger R/T with factory power disk brakes and factory rear drums. I am going to keep the factory power booster.

So which bore size do I need? And any recommendations of a supplier? Preferably someone who actually responds to requests from prospective customers.

Thanks