Hi,
Something doesn't sound right. Both cylinders 1 and 6 should be at TDC which is normal, but they are at different phases of combustion. What I think happened is when the timing chain sprockets were aligned, they placed the cam sprocket at 12 o'clock rather than 6.
The best thing to do is remove the timing chain cover and inspect the timing marks. I attached a pic below and highlighted where the marks should be if they are correct. What I think has happened is they placed the cam sprocket at 12 o'clock. Thus, it's 180° out of time. Cylinder 6 is on its compression/firing stroke rather than cylinder 1. The cam lobes are 180° off.
The red line pointing up indicates where I think they had the timing marks.
I hope that makes sense.
Let me know if you check it and what you find.
Joe
See pic below.
Image (Click to make bigger)
Monday, May 3rd, 2021 AT 5:49 PM