David, the only gasket you need is the one numbered 15066. I would change your oil gauge sender first before I changed any of the other parts. If you still get readings that you consider low, I would think about changing the oil pump.

I don't recall what my cold oil pressures were, but I don't think you are seeing anything dangerously low. Especially if you haven't warmed up the motor and rev'ed it up to see what you are getting under load.

If you do change the pump, take all the spark plugs out and turn the motor with a socket on the crank. Shine a flashlight in the spark plug hole of cylinder#1 and you will see the piston at TDC. Use the distributer and the timing marks to make sure that you are at the proper stroke.

Be sure to prime your oil pump before you put it on. Just fill it up as much as you can by pouring some oil in the holes (but not so much that it spills all over the place when you turn it at an angle to put it in).

See what Earl said about the distributer.