It depends on how you put the distributor in. If you're asking this question now it probably means that you didn't have the engine at TDC when you took out the old distributor and put in the new one... now you get to track down TDC on the engine (that's when #1 cylinder is at the top of the compression stroke) and find out where the distributor is pointing.
Understand that the #1 piston will be at TDC on top of the compression stroke and on top of the exhaust stroke. You need to make sure it's the right TDC. At that point, wherever the distributor is pointing is #1. Unfortunately, not everyone makes sure the distributor is back to factory specs.
The #1 cylinder should be the first plug clockwise from the electrical connections on an HEI distributor. Or, the first plug clockwise from 3 O'Clock when facing towards the rear of the vehicle.
Clockwise
clockwise
To advance, rotate the distributor counter-clockwise. To retard, roatate it clockwise).
Rtr. turning clockwise. Rotate distributor counter clockwise to advance timing, clockwise to retard.
Clockwise.
counterclockwise
The way the rotor rotates retards. If the distributor turns clockwise, then turning the distributor clockwise retards the timing.
Clockwise
It is clockwise
The rotation is clockwise.
clockwise