Is the 4.6 liter motor in a 1996 ford thunderbird vin 6?

No. The 1996 Ford Thunderbird did not offer a 4.6L engine. The VIN code doesn't directly tell you the engine size, but the available engines were smaller. The VIN's sixth digit helps identify the engine *family*, but it's not a precise engine size indicator. A 1996 Thunderbird would have had either a 3.8L V6 or possibly a 4.6L V8 in later model years, but not the 4.6L in 1996.