Well, it's my turn to ask for suggestions..

Good find, and what I was going to suggest. Thanks for reporting back w/ details. But, I'm confused by your timing set. The one I used in my 273 had 3 different marks - dot, triangle, square I recall. One matches the pair for the desired timing (+4 deg, straight, - 4 deg), though the symbols were a bit hard to make out. I would be even more confused by yours. I hope it had a clear instruction sheet, not one of those "everyone knows" assumptions. I was also confused that the dots lined up when #6 was on TDC compression, when I expected #1, but found that is correct. I used a cam w/ about the same lifts (0.422/0.440), termed "RV Torquer". I care most about smooth idle and good mileage.