Timing on our old inline 6 engines is an exercise in old school training. With the changes to fuels over the years the only "good" way to do it is as Tclederman has described. A Vacuum gauge is your friend. The "Ball", "BB" or TDC will get it started(these are not fussy engines to start). The Vacuum gauge will get you real close. A quick trip up a hill will tell you if you are too advanced(it will "ping") You can use a hi-tech timing light to tell how much advance you have. If it matters to you(tuning for performance?) but these run well when set to the Vacuum gauge.One thing to keep in mind, the mark will line up at #1 TDC or # 6 TDC, so it matters to find which one is on compression. I take the valve cover off so I can see and feel the rocker arms. It is also nice to see the oil on the rocker shaft at the same time. Proof that all is well sorta comforts me.
