Classic/Antique Car Repair: ignition timing, yellow marker, paint type

Question
Hello I have a chevy step van with a 6-250 engine It has timing marks between the pulleys which I cant see and on the bottom by the oil pan. If Im reading the ones on the oil pan the timing light isnt seeing the marks right. Do I keep the module on the number 1 cylinder? And if I do how can both timing marks be in the same place at the same time?  

Answer
Don;
Hi  you might have to clean them off good and than with a white or yellow marker (paint type)  put some on the marks than thay will show up good.you should see the 2 marks side by side when running at a idle .To adj. the timeing you will loosen the dist a little and turn it slowly,you will hear/see the engine go up or down do it slow. till the marks are set.