That's the wrong shifter David. The part number is 45051 and unfortunately B&M don't make them any more.
The last couple of boxes I've built I've machined up my own shifter bases rather than adapting something else.
Starts put with a new plate machined to the right dimensions and bolt holes.
Machining for the shifter insert.
Finished Shifter
Installed and ready to go.
Cheers