273 camshaft selection help

A '69 273? 1st 2 years had odd bolt angles and 5/16 screws, so, the intakes are hard to come by.
Otherwise, ethier a LD4B or Performer from Edelbrock and a 500 cfm carb will handle most duties.
Now about the cam.....what gear ratio and tire size do you have? Headers or manifolds?