The crankshaft rotates twice to cycle through all 6 cylinders.

Therefore the timing mark on the flywheel show up twice - only on one of those two times are both valves closed for the #1 cylinder .

You'd be 360 degrees off.

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.