Lots of good info here: http://www.buicks.net/shop/engine_ident.html VIN is on the driver side dash, of course, and the engine s/n is located on the front of the block on the driver side. The last several numbers of the engine s/n will match the last several #'s of your dash VIN if it is the original engine.
The VIN plate should be on the firewall, just inside the windshield, on the drivers side of the car. If you didn't look before buying your car, I hope this VIN matches your title :laugh: It's about 6 inches in from the driver's side windshield post and about 2 inches from the base of the windshield. Added in edit - The VIN plate is in the same location as your '68
