"...the 186905 is or should be part of the VIN of the vehicle."
I think the numbers he posted are those found just above the YS code.
The numbers which will match the last numbers of the VIN, are located down by the lower part of the timing cover, on the passenger side.
Here's what the Wallace site says about the partial VIN:
"Pontiac stamped the VIN numbers next to the timing cover about even with the timing marks on cover.This will start with a 2 (for Pontiac) then the last digit of the year then the car serial number starting with the plant letter.These are usually covered with oil and crud, and probably hard to see.This will tell you if this is an original motor."
Last edited by oldskool; 11-12-2015 at 05:37 PM.