So with the timing mark on the crankshaft pulley at TDC with the pointer, either the number 1 piston could be at TDC on the compression stroke or it could be the number 6 piston at TDC on the compression stroke. You have said that with the timing mark at TDC your rotor is at the 2 o'clock position. If the spark plug wire on the distributor cap at the 2 o'clock position goes to the number 6 spark plug, then your distributor position is correct and does not have to be changed. If the plug wire at the two o'clock position on the distributor goes to the number 1 spark plug then you distributor is installed 180 degrees out from the published position . To correct it, you can pull the distributor up about 1/2 inch and rotate the rotor shaft until the rotor points to the 7 o'clock position then push the distributor back down into the block and reinstall the retaining bolt. then you have to reinstall the distributor cap and make sure the plug wires go to the correct plugs. Starting at the 7 o'clock position of the distributor that plug wire should go to the number 1 plug. Then in a clockwise rotation the wires should be landed according to the firing order: 1,5,3,6,2,4. Regards