Getting ready to install my new Wilwood 4-wheel disc brakes on my '68 RR and have a question about the new M/C.

My current M/C is a stock-style Mopar M/C with 4 mounting bolts to the firewall. The new Wilwood aluminum M/C is a 2 bolt installation. Is there an adapter plate I need to buy in order to install it?

Also - I ordered the 7/8" bore M/C.......is this the right diameter for the car? I went with 12.2 (6 piston) on the front and 12.2 (4 piston) on the rear.