S-Code Mustangs are very popular. Check out the prices on ebay for a comparison, they always move for over 10-15K, even the ratty ones. Sounds like the one you're looking at is beautiful. Tons of power in the straight line, but can be a handful going around corners!! 390 is a heavy engine, makes the Mustang a bit nose heavy. I actually saw an X code '67 this spring up here in MA. That's a 390 with a factory installed 3x2 intake. It was fully documented and restored.