Maybe, I'm not sure if the LA has the same bolt pattern. I know the OS .46AX and FX have the same pattern as the Tower .46 (and the Thunder Tiger .46 and some others as well), but I'm not sure about the LA. If you look on the OS engines website or tower, you might be able to look up the bolt spacing to see.

As for adding power, it will add a little, but it's not going to turn the LA into something as powerful as the Tower .46, the Thunder Tiger, or the OS AX.