No, there's a star washer sort of thing that goes on the shaft -- you'll put that end down in the block, toward the distributor. That'll keep it in place. Then you'll put the oil pump housing in, and bolt it all down. The reason for that washer is two-fold. It prevents the oil pump ds from coming out if you pull the distributor out at some point and it keeps it in place when you're installing the oil pump. It must be installed -- imagine this scenario...You pull out your distributor to move it a tooth over to allow for more timing adjustment. The driveshaft is stuck in the bottom of the distributor, pulling it out of the oil pump. it then drops out of the distributor, falling into the oil pan. You're next step (after smashing the distributor on something) is to start removing the oil pan to fix it... Not a good scenario. You want to have a little play - don't make the star washer length so tight that it can't move at all. Compare it with the stock one if you still have it around -- should be a good starting point. The ARP HD shaft is good. If your oil pump ever seizes, it'll snap your distributor, causing your motor to shut off. The stock one or the one that comes with the melling pump would just twist into a pretzel, allowing the motor to run without oil.
- Jeff