Engine Mount Bracket

All i've ever done when rocking v6 engines forward is remove dogbone like you already have. You can only rock forward so far.

Just to add to this one they also sell a tool that pulls and holds the engine forward that goes where the mount fits.

Here is what I have on replacing the lower intake manifold.
Removal Procedure

Important: The fuel injector wiring harness connectors must be connected to their respective fuel injectors. Failure to connect the fuel injector connectors to their respective fuel injectors may result in excessive exhaust emissions and poor engine performance.

Disconnect the battery ground (negative) cable.
Remove the upper intake manifold.
Remove the engine left side valve rocker arm cover.
Remove the engine right side valve rocker arm cover.
Disconnect the wiring harness from the Engine Coolant Temperature (ECT) sensor.

Important: Use masking tape or another appropriate method in order to identify each fuel injector wiring harness connector cylinder number.

Disconnect and remove the fuel injector, Manifold Air Pressure (MAP) and ECT wiring harness.
Remove the fuel feed and return pipe from the fuel injector rail.

Remove the fuel injector rail.
Important: Do NOT disconnect the power steering pipes or hoses from the power steering pump.

Remove the power steering pump from the front engine cover and reposition aside.
Disconnect the heater inlet pipe with heater hose from the lower intake manifold and reposition aside.
Disconnect the inlet radiator hose from the engine.

Disconnect the thermostat bypass hose from the lower intake manifold pipe.

Remove the lower intake manifold bolts.

Remove the lower intake manifold.

Loosen the valve rocker arms and remove the push rods.
Remove the lower intake manifold gaskets and seals.
Clean the lower intake manifold gasket and seal surfaces on the cylinder heads and the engine block.
Clean and inspect the lower intake manifold.
If you are replacing the lower intake manifold, remove the ECT sensor.
If you are REPLACING the lower intake manifold, remove the thermostat.
Installation Procedure

If removed, install the thermostat and the thermostat housing.
If removed, install the Engine Coolant Temperature (ECT) sensor.
Apply 8 - 12 mm (0.08 - 0.11 inch) bead of RTV Sealer GM P/N 12345739 or equivalent on each ridge where front and rear of the lower intake manifold contact the engine block (1).

Install the lower intake manifold gaskets.
Install the push rods and tighten the valve rocker arms.

Install the lower intake manifold.

Install NEW lower intake manifold bolts.
The torque specification is a 2-step process; tighten the vertical lower intake manifold bolts (the four middle ones) to 7 Nm (62 lb in). Tighten the diagonal lower intake manifold bolts (two on each end) to 7 Nm (62 lb in). Tighten the vertical lower intake manifold bolts (the four middle ones) to 13 Nm (115 lb in). Tighten the diagonal lower intake manifold bolts (two on each end) to 25 Nm (18 lb ft).

Connect the thermostat bypass hose to the lower intake manifold pipe.
Connect the inlet radiator hose from the engine.

Connect the heater inlet pipe and heater hose to the lower intake manifold.
Install the power steering pump to the front engine cover.

Install the fuel injector rail.
Connect the fuel feed and return pipe to the fuel injector rail.

Important: The fuel injector wiring harness connectors must be connected to their respective fuel injectors. Failure to connect the fuel injector connectors to their respective fuel injectors may result in excessive exhaust emissions and poor engine performance.

Install and connect the fuel injector, Manifold Air Pressure (MAP) and ECT wiring harness.

Install the wiring harness to the ECT sensor.
Install the engine right side valve rocker arm cover.
Install the engine left side valve rocker arm cover.
Install the upper intake manifold.
Connect the battery ground (negative) cable.