Schumacher motor mount installation

Has anyone installed the BB Schumacher conversion motor mounts. I am getting ready to put them in and I am wondering if it is absolutely necessary to cut the ears on the perch and drill the holes as it says in the instructions. I have only looked at this and have not tried it yet but it says it is necessary to make room for an oil pump. From what I am looking at they should just bolt up and sit just like the factory ones. maybe I am missing something here but need some input. This will probably mean pulling the engine and tranny out to do this. any help would be appreciated.

Slant 6 K Or V8 K?