Can anyone give me a ruff value on a 51 Buick Special?

I have a 99 Cadillac Eldorado valued at about $7,000.00 someone wants to trade me for a 51 Buick Special. It looks like he put A lot of time into this car with modifications to the body and interior of the car, still has the original motor and transmission, and is currently primed for paint.|||Check the Hemmings Motor catalog or Hemmings.com to get an idea on the price. Keep in mind that modification to the body and interior lower the value of the car. There is an exception to the "keep it original" rule and that is in muscle cars. There is now a following for hot-rodded muscle cars including larger than stock engines, etc. But a 51 Buick is not such a car and should be kept entirely original and stock to retain its value.|||Check wit barrett-jackson.com the auction classic cars but yours isn't ready.