The mounts bolt up to the same ones as the original Olds mounts; no drilling required. I hit the holes with a little silver spray paint for clarity.
One of the original mounts
This shot gives a better idea where the engine mounts up:
Mocked up (trans isn't in place yet)
The last shot shows my trusty TPIS "Happy Hooker"...its an older one, but we drilled it for LS engines as well as several extra carb patterns.
The old gas tank is also out, but no pics of that yet.