If you come across the problem where you can't turn the distributor enough to set the timing properly because it hits either the plug wire support or the side of the #8 intake runner first, the distributor drive gear has been installed wrong.
There's a machined "dimple" on an OEM Delco drive gear, and it's supposed to be assembled on the shaft such that the dimple faces the same direction as the tip of the rotor.
There are 13 teeth on the gear, so each tooth is 27* of distributor shaft rotation; with the odd number of teeth, the gear is either on correctly or it will rotate the distributor body 13.5* from where it belongs if it's installed wrong. The entire OEM system, from the pin on the front of the cam to the drive gear on the cam to the drive gear on the distributor shaft with the "dimple" on it is very precisely indexed in machining so the distributor body ends up in the center of its travel, with the same clearance on each side, when the timing is set correctly.
If you have an aftermarket cam (or distributor), they pay no attention whatsoever to the precise indexing on the factory cam and distributor drawings, as they don't understand why it's necessary, so it's the luck of the draw whether the distributor ends up centered; if it isn't, knock the rollpin out of the gear, turn it 180*, and re-install the rollpin, and it'll move the distributor housing 13.5* so you can set the timing with the distributor properly oriented.