top dead center

[slugish]

forgot to mark my distributer when I removed it for new heads & cam upgrade . What is the best (or simplest way to find top dead center so I can mark my damper . Its already marked , but Iwas told Ihad to find top dead center on the compression stroke & mark it . Was told one way : get a plug stop-put it in # 1 cylinder plug hole --rotate engine clock wise till it hits - mark spot on damper-then rotate counter clockwise till it stops again - mark damper again - measure the distance between the 2 marks - top dead center will be 1/2 way between these 2 marks . How do yall do it

Thx Will