2006 Ford Five Hundred Engine?
 

How can tell which engine I have?

3.0L 2968CC 181Cu. In. V6 GAS DOHC Naturally Aspirated
or
3.0L 183Cu. In. V6 GAS DOHC Naturally Aspirated.

They apparently have different intake manifold gaskets.

FordEtis:
Primary Features
Build Date: 19.08.2005
Vehicle Line: Taurus/Five Hundred/Sable/Montego
Body Style: 4 Door Saloon
Version: SEL Version
Engine: 3.0 V6 24V DOHC EFI Modular
Transmission: 6-Speed Automatic Transaxle - AWF21
Drive: LHD FWD
Axle Ratio: 3.46
Emission: 50 State Emission Requirements
Air Conditioning: High Capacity Air Conditioner
Territory: (+)"USA"
Paint: Dark Shadow Grey