383 timing set question

Hey y'all,

Was installing my new timing set on my 383 and according to my FSM and the instructions that came with the set, my timing marks should be at 6 o'clock (cam) and 12 o'clock (crank).
This isn't the case, I'm clearly at TDC #1 as the rockers are totally unloaded. .. further, the crank and cam are exactly where I left them... ain't no way the cam rotated 180 degrees on its own.
What do you all think? I rolled it over and there was no interference..

Thanks everyone and best...

383 timing set question
Author: GJS