What is a 1973 Jaquar XJ-6 Worth?

I am presuming that you are refering to a series 1 XJ6 which dates from 1968 to 1973. According to a British price guide a right hand drive car is worth between £600 for a condition (3) 2.8 to £5500 for a condition (1) 4.2 Hope this is of help.