The linkage kit from Holley will have a bushing that will fit in the large hole, that should accept your older style linkage arm.
http://www.holley.com/types/Throttle...ce%20Parts.asp
Also... if that is a used Holley... make sure the floats are set correctly , and see what jets are in it before you go much further. Some cats will get all wonky with Holleys thinking they have to constantly tune them. Which you don't. So who knows where the floats are set, and what jets are in it.
It already looks like the accelerator pump has been "adjusted" too much.
Are you gonna rebuild it before you install it?
What rig is this engine in?
Gary