The recent post on distributors reminded me to question the pump drive shaft in my 272. I've measured my Cardone distributor shaft length and it is 6" from the mounting surface. My pump drive shaft doesn't have the retaining clip and the shaft comes out with the distributor when I pull it. I have to reverse the direction of the shaft to unlock it so it will come out of the distributor. I haven't measured the amount the pump shaft goes into the distributor drive shaft, but it isn't much, maybe a quarter inch.  That brings me to ask the questions: How much should the pump drive stick into the distributor shaft? Are there different lengths of the pump drive shaft, or what is the correct length? This shaft has a sharp point on one end, while the other end is somewhat rounded. Thanks for any advice. Gene