Engine and Transmission Tech

I started with a set of engine mounts from D&D which fit fine with the 3.5 engine that I have, the engine is a 1988 block. But in an effort to lower it a bit I bought a second set of mounts (brackets & pads) from Glenn Towery. When I did a test fit on them I run into an issue I am not sure what to do about, on the driver side of the block where the engine mounts there are two casting pieces with threads in them that will not allow Glenn's mounts to sit flush to the mounting holes on the engine. Can anyone tell me what those are for? I have looked through the V8 book and don't see anything being mounted at that point, which is on the block lower driver side above where the oil pan attaches. I can post a picture if it will help but looking at the Olds block I have there are no such holes so I don't know if I was supposed to have this area ground down by the machine shop or not. Any ideas? Thanks! Michelle