I hate to be a broken record, BUT they make engine programs that will predict what octane fuel an engine will need, and for example if you have to run pump gas, it will calculate an advance curve to safely do that as well. Program I use is less than $200 and I have been using it for many years. It may not be perfect but it gets you a lot closer than asking suggestions. It also predicts cranking compression, idle vacuum, and a bunch of other stuff. If you take the time to enter flow bench numbers, and calculate the REAL static compression, etc. it has hit every engine on a real dyno within just a few horsepower. I set up a pump gas procharged 410 LA engine, and simply ran the numbers in the program without boost and then with boost, plugged those numbers into the timing maps on the Fitech, and it ran perfect, just one example. I have a distributor machine, and when I build a street engine I calculate the advanced curve, set the distributor to that curve on the machine, and have yet to have an issue. I still look at the heat mark on the electrode, but they are always right where it needs to be.