Ever had a woman tell you, you better watch it when your maybee doing a river crossing in your 4 by 4. You do it anyway, and you hydraulic it, or get the diff caught and busted on a hidden boulder. Well, ignition is like that. It suffers the commentators curse, because a piston engine is detonation limited. Read Frenchtwon Flyers missive on how Ford set the advance curve and compression ratios on there engines. They spend millions on it just to ensure they don't break customer engines. And with just a few degrees and a timing light, we can undo it all.
Back in the day, Keith Duckworth said anytime an engine needed heaps of lead, it was because the combustion chamber is inefficent. So try to run less lead initial and total than what the engine runs best with, always.
The last Boss Mustang I dorve had 16 degrees static is what you'd see on a 290 degree car with canted valve head, same as what you'd use on say a X-flow 250 with the wildest cam. On my more modern 24 valve V-6 EFI, edis-6, alloy head 9.7:1 compression 87 octane runing 4 liter 205HP Exploder, it sits on 17.5 degrees at 600 odd rpm, and I've never seen more than 37 degrees total on it yet. I've seen it drop back to 5 degrees on trailing throttle, and 15 degrees under wide open throttle at 3500 rpm, where maximum torque comes in. That's a lesson to us all.
Though a stock engine will take that much advance and idle and sound fine, its hurting emissions and running close to heating things up. A conservative 9 degrees is better of emissions, and better for safety. 34 degrees total lead is a line that I'd never like to see transgressed on an I6.
Stock emissions engines have a raft of reasons for not going crazy on static advance, and the big big bang will stop an I6 in short order, they will sound nice until the stock rings loose it, and the outer cylinders lean out. Cylinder 5 and 6 can misfire and result in detonation, and you won't get any warning BEFORE IT DOES SUMMIT ORIBLE.