OK , in school we haad to learn timing and it just seems to be that a engine does need more timing but remember timing is fluid and is a result of combustion chamber design.
So as a drag engine builder I see several different engines in a single tuning session.
Well several years ago one of the engine builders had his engine set up with a reversrotation cam and left his distributor loose after resetting timing and at the top end his car made better trap speed and went slightly faster.
Well this guy found the loose dist never put 2 and 2 together till some time later when he figured out the collar had cracked on the dist and at high rpm it started slipping back all the time.
Anyway they found on the dyno how he made better runs when dist was loose, the engine wanted retard on the top end. Now dont get this wrong not all engines want retard on the top end BUT under boost most engines want some type of retard.
AGAIN let me reitterate, this is dependant on chamber design and air/fuel distribution as some engines will just want to keep advancing.
BUT also remember we have people out there using locked distributors and a flat amount of timing with no advance.
BUT for me i have found pretty much any engine needs some type of non static advance that is RPM sensitive but it needs to be able to go both ways.
It was either Arnie "TheFarmer" Beswick or or one of the old super stockers of the time that used a simple throttle cable through the firewall and a loose ditributor and would retard his dist by as much as 20 degrees on the top end ,and all while shifting a 4 speed too!
As for timing and octane rating of fuel , we should keep the forum posted numbers in R+M/2 rather than RON or MON as one will be high than the other but can switch between brands. The best fuel I have here in Indiana other than E85(105 R+M/2) is Sunoco Ultra which is 94 (R+M/2) Also its getting better as now we have been mandated to use Ethanol over MTBE federally and I like it much better as the alcohol makes it easier to read plugs as MTBE can cause wierd plug colors and isnt as safe or renewablew as alcohol. And alcohol makes a better oxegente and adds octane rather than just adding an oxegenate.
We just took a 355 with AFR aluminum heads to the dyno and I used a 10 degree retard and it was still picking up power after 5 different pulls. Now we ran out of time and had to shipp the engine so I gave the owner some instructions on the ignition setup(Holley Pro Strip Anihillator) and to keep pulling timing out on the top end.
Amazingly the plugs kept getting cleaner on every pull.
The engine made best timing with 20 initial and a advance total of 61 and we kept trying to vary the low end peak and the engine kept wanting a faster and faster curve up to the owner stated cruise rpm of 2650 (I try to get all my timing in by cruise speed. At a steady pull we let it advance to the total of 61 BTDC. Now figure this was then retarded on the NOS pull (250 shot) by 10 degrees and then at top end had the other 10 pulled so it was yanked back to 40-41.
The owner of thedyno had never seen anyone use retard to get better peak torque readings, as most people try to hit better average HP/LB FT over a dyno pull.
I learned that a flatter, higher torque curve always gets me a harder pulling engine.
Its all in learning to give the engine what it wants rather than completely copy other tuners work which may be a great place to start but you gotta set your engine up as it is unique.
I built 7 "spec SBC" engines and none of them dynoed exactly the same and trust me we had every cylinder down to .0001 +or- ,cranks same, bearing clearances , valve spring seat preasures, Literally as identicle as I could get them and they all varried from 7 to 10 lb ft of torque from each other AND none had exactly the same timing curve(all used same dist/box setup and carb and none had same carb jetting) kind of makes a fella wonder so I labeled his engines from lowest to highest and he never had a problem as even as he hurt an engine he was putting in a faster engine (and he had all the tuning specs to start from on each so he could take it from where I started)
Just remember timing is fluid and every engine is a simple fluid pump and it takes time to tune an engine even with a set fuel/ignition setup let alone open sourse/prototyped like Megasquirt.