Unfortunately, there are no deductions you can take for gifting this car to your son.
INstead, if the car was valued at more than 12,000 dollars (using blue book value or other appraisal method), then you would have to file a gift tax return with the IRS. But, if you have not exceeded one million dollars in such gifts in your life time, you would not be assessed any gift tax.
LOL...no offence...I understand. Here is some good news; as a gift, your son does not have to pay any taxes.
The IRS is like getting sticky stuff on your fingers and then trying to get it off with luke warm water, using toilette paper.