That's the bottom bolt for the upper timing cover, not the distributor cap.

You will need to remove the coolant pipe in order to get to the bolt. Drain the coolant from the radiator and the block to prevent too much coolant spillage. There should be two bolts, one in the middle that bolts to one of the timing covers or brackets, and one on the water pump. Loosen the first, remove the second, then the pipe should come out by pulling towards the passenger side.

Oh, and take the rubber coolant hose off the passenger side of the pipe before removing.

You should get a replacement rubber o-ring for where the coolant pipe interfaces with the water pump. If your other hoses are old, this would be a good opportunity to put in new hoses and hose clamps.

Anthony