The actual cylinder number six.
The reason I did the setting order like that is you can work your way thru lash setting in only two complete turns of the crank [1/4 turn at a time] and the cyl you are working on will be above or below the one with the valve's rocking.
Example- Set #1 with#6 rocking, Set#5 with#3 rocking, Set#4 with#7 rocking, Set#2 with#8 rocking, Set#6 with#1 rocking, Set#3 with#5 rocking, Set#7 with #4 rocking, Set#8 with#2 rocking.
All of this is easier with the plugs removed. When you bring the crank round to TDC watch the valves on cyls #1 & #6. One or the other will be in the rocking[ex closing/in opening]. If its #1 rocking turn the crank one more complete turn so that you can start your lash settings on #1. The front pulley can be marked with a piece of chalk or tape for each 1/4 turn[90deg] to help the process if you desire. I see a few guy's advocating the use of 'bump' switches. I prefer to remove the plugs & turn the crank with a ratchet& socket on the nose of the crank, or if your working on a smooth shop floor put the trans in top gear and rock the car forward to each checking point[ that may be difficult on Cobras w/o flip front ]
While JAY has the actual cyl numbers in the correct layout, he has superimposed them on a CHEV block, which staggers the bores the other way from Ford blocks. Hopefully that will only confuse the chevy owners who browse this forum looking for ideas.