Each torsion bar has the manufacturer and the last three digits of the part number stamped into the flat surface on the end. This vendor code, "UKA," remains a mystery. The number "781" is a Six Pack or a Hemi bar. These numbers are important because they are the correct application for the particular suspension and they correspond to the color codes (it corresponds to the numbers on the list to verify the color codes). Simply find out your part number, then refer to the chart on page 42 for the left and right torsion bar color codes.