This is not difficult. When gifting something, the cost basis of the giver is also gifted.
When you sell the property, the FMV does not play into anything at all. So you can throw that number out. Your cost basis is what you paid for the property when originally purchased, (in your case, $1921) plus the cost of any and all property improvements done since that property was originally purchased for $1921 by your father. It does not matter who did or who paid for the property improvement. It does not matter if the property improvement was done before your dad gifted it to you, or after.
