The vin # is for engine size. The engine code is the eighth digit in your vin. The 1 is classified as the 3.8 sfi s/c or l67 engine. If you want more info, check out this link for more on decoding your vin. My car has an l36 (vin k) which is the 3.8 n/a.

Vehicle Identification Numbers (VIN codes)/GM/VIN Codes - Wikibooks, collection of open-content textbooks