5.7L Ignition Timing Table - Feedback

Hold on a second before you change anything. I don't agree with those above. The table is not flipped, it just has a different meaning than you guys are thinking. That is not engine "vacuum" that is being measured exactly. Higher kpa numbers does not mean more vacuum. The chart reads absolute pressure, so 100 kpa is roughly atmospheric (or wide open throttle), and 0 kpa would be near total vacuum. It's usually better to think of it as engine load as a percentage, though maybe that's not exactly 1:1 in ratio, but probably close enough since 100 kpa ~ 100% on a naturally aspirated engine. Boosted engines change this around some.

I think your max load numbers look pretty good. They say the modern Hemis don't like much more than 21-22 degrees all in and that appears to be what is in there. As for low load/cruising, you can probably get away with more, but it's up to you what you want to tune for. In datalogging the newer Challenger my dad once had and our Ram truck with Hemis, they would command nearly 40 degrees of timing at very light load. Realistically though, unless you are really trying to lean it out and optimize gas mileage in cruise I wouldn't worry about it much.