I think it is a 1968 Cutlass convertible? with a V8 Built in Lansing Michigan. I know the vin breakdowns are in the chassis service manual but loaned mine to a friend. There shouldn't be a letter where the F is in the body code, should be a number unless it is something not in the books. I figure it's a convertible but could be a 4 door or vista cruiser with the 6 first in the body code. I linked to a site with breakdowns if you want to try and figure it out. Hope this helps.
Allan
http://www.oldsmobility.com/vin.htm