How close are the timing marks.

one time while building a chryslet 392 hemi early type. i was using a 354 vibration damper. but the marks was on the wrong side of the block. so we made new ones. we did the math to find the length of the total making. then double checked against the 345 marks and the 392 marks. we used punch marks. like 5 punches for 10 degrees, 2 punches for 2 degrees apart. 3 punches for 5 degrees. we took all after noon to be sure it was as right as we could get it. it worked fine. but the old hemis dont like a lot of timing, on gasoline.