Please advise per the attached pic if it's possible to trim/remove the protruding part of the garage foundation block to be at the same level of the baseboard above it.
The curbing should not be removed. It is typically an integral part of the wall foundation structure and may even have rebar embedded in the part that you think that you want to remove. The curbing is almost always installed as part of the foundation wall before the floor is ever poured. The width of the curbing is typically equal to the "thickness" of the foundation wall with inside to outside dimensions specified by codes, design requirements, geographic location and load bearing requirements.
These curbings provide important functionality in several ways:
- Provide anywhere from 4 to 6 inches of additional ceiling height in the garage when standard length studs and standard sized sheathing material is used to construct the walls. In many cases this allows the needed overhead working space for overhead garage doors.
- The curbing raises the wood components of the wall structure up off the floor so that when water enters the garage or a wash down is done it keeps from soaking the wall wood.
Garage walls are often framed with 2x4 sized studs and plates. A curbing that was poured to just match the width of the studs and plates is just too easy to break or crack. This is a key reason you will see the curbing wider that that.
One choice you have if you cannot stand to deal with the curbing is to add additional studding to the walls to bring a new wall surface out even with the inside face of the curbing.