60 degrees is exactly what Mopar Performance engine book says not to be surprised by including vacuum advance. They go into great detail how to get a correct timing curve and how to include and adjust vacuum advance. I remember when I was a kid, the FIRST cardinal rule when you got a Mopar was to buy either the Direct Connection or Mopar Performance engine and suspension books.......and you know what? We never had any of these prolific problems a lot of these guys are having. Having problems with timing, running hot, drive line vibration from incorrect pinion angle and on and on and on.