I am installing the distributor on my 1962 261 ,TDC #1 ,#6 the valves are rocking, there is some different marks on flywheel ,looking through the timing hole. There is a little circle and very close to this there are 2 lines and beside that there is a triangle. What is the timing mark supposed to be?


1962 GMC 920 step side 261 4 spd