Motor builders

Hmm, I didn't know that about the STS-V.

The only tag on the new CTS-V engine that I see is the GM Performance Division tag at the front.

From the site you quoted above, the CTS-V's engine is built in the Silao, Mexico plant that builds the marine engine and several Chevy truck models. Interesting to know. Here's the full specs from the GM site listed below.

http://media.gm.com/us/powertrain/en/product_services/2009/09car.htm#62L

2009 "LSA" 6.2L V-8 ( LSA ) 60908
Type: 6.2L Gen IV V-8 Small Block
Displacement: 6162cc (376 ci)
Compression ratio: 9.1:1
Valve configuration: overhead valves (2 valves per cylinder)
Assembly site: Silao, MX
Valve lifters: hydraulic roller
Firing order: 1 - 8 - 7 - 2 - 6 - 5 - 4 - 3
Bore x stroke: 103.25 x 92mm
Fuel system: sequential fuel injection
Fuel Type: premium required
Fuel shut off: 6200 RPM
Emissions controls: catalytic converter
three-way catalyst
positive crankcase ventilation
Engine Orientation Longitudinal
Valves per cylinder 2
Bore Center (mm) 111.76
Applications: Horsepower: hp ( kw )
Cadillac CTS 556 hp ( 415 kW ) @ 6100 rpm SAE CERTIFIED
Applications: Torque: lb-ft ( Nm )
Cadillac CTS 551 lb-ft ( 747 Nm ) @ 3800 rpm SAE CERTIFIED
MATERIALS
Block: Cast aluminum
Cylinder head: A356-T6 rotocast cast aluminum
Intake manifold: Cast aluminum
Exhaust manifold: High silicon / high moly cast iron
Main bearing caps: Nodular Iron
Crankshaft: Forged steel
Camshaft: hollow steel
Connecting rods: forged powder metal
Additional features: 1.9 L/rev Supercharger
Integrated single coolant to air intercooler
Piston oil spray cooling
Direct mount ignition coils