While prices have fallen, so has the quality of some ignition parts. Luckily, we work with a number of suppliers here and abroad who are reversing the trend. A good example is this heavy duty ignition rotor. Some background: recently manufactured rotors are not like what Lucas manufactured when classic Jaguars were new. Newer rotors have much more carbon black in the plastic, which increases its conductivity. Original contacts were molded into the rotor body; replacement rotors use a rivet, the tip of which is very close to the spring clip on the underside of the rotor. Because the high-energy spark from the coil will follow the path of least resistance, this path can pass through the rivet and spring clip and ground out on the distributor shaft. This will cause a "miss" that will only go away temporarily when things cool down. Our new heavy duty rotors are made from a non-conductive resin and the brass contact is molded to the body; no rivet means no chance of conductivity. Finally, the socket is precisely sized for a tight and accurate fit. Highly recommended. The DRB106 rotor fits all XKs, all six-cylinder E-Types, all early sedans and XJ-6 Series I and II with points.