I know the theories, but what about REAL world applications?
I have a 440 stroked to 493, 10.8 to one with aluminum heads. MP '509 cam straight up. With the highest octane pump gas, I have to limit my spark advance to 31 degrees. I have looked at charts showing varying compression ratios depending on combustion chamber volume. It looks like each CC of volume equates to about 1/10 of a point of compression.
My thoughts are: Putting in thicker head gaskets to lower compression slightly, allowing MORE spark lead, leading to more power. The Fel Pro head gaskets in my mill are .039 compressed. There are off the shelf composite gaskets with .051 thicknesses as well as custom Flatout or Cometics with made to order specs. A .060 gasket will likely only lower the compression 1/2 a point. That MAY be enough to ward off detonation, but its only a guess.
I am fully aware of the limitations of the MP '509 camshaft. I used it for this build because I already had it along with the matching lifters. I've considered switching to a modern cam. I ran 2 different Comp XE285HL cams in the past. Better idle and slightly more power. I am unsure which change would give more benefit: The thicker head gaskets with MORE spark advance OR the modern camshaft. Any opinions?

If you unhook the vacuum advance does it still ping if you give it some more total??
your close to what 93 should allow. you could go up a couple jet sizes and try that. you did not say what carb and jets.

how tight is the converter?

You've got EXACTLY the same engine as mine. Same cubes, same CR (I calculated mine at 10.9:1, but close enough), same cam, aluminum heads (mine are Eddys, you didn't say what yours are). I have a Performer RPM with a 850 VS Holley.

I have no problem at all running 35 degrees total with a quick-ish curve. I have about 12 degrees of vacuum advance and use whatever 93 octane pump gas is handy.

How's your carb tune? Have you checked it with a wideband meter or a 4 gas meter on a chassis dyno? Barring that, how's the spark plug color?

well if your engine has good quench now running a thicker head gasket to lower compression is going to hurt more than it helps. additionally what rpm are you at full advance? you could delay that out a little. how hot is it running? how much does your car weigh? what gears? converter? tire size? air/fuel ratio? what spark plugs? lots of things that make a difference.

If you have good 0.040" quench, thicker head gaskets may make the pinging worse even though the compression is slightly lower.
I'm calculating the cranking compression pressure should be about 153psi? which should be ok, but with the hydraulic cam if the lifters are bleeding down it will make the cam seem smaller and raise cylinder pressures.
Anyhow, if pulling the heads, I would try to maintain good quench clearance, and take a few cc's out of the cylinder head chambers, unshrouding the valves and polishing the chambers.

Octane is octane no matter where you are. You may have more ethanol (actual 10% vs mabey 10%) but ethanol helps ward off detonation not increase it.

Something else is wrong, like too much vaccume advance, too hot of engine temp, too lean of carb mix... that cam should be more than enough to bleed off any excess compression unless it is advanced too much. I would check over the combo real good before ditching precious compression and possibly quench. What pistons are you running and how far are they above or below the deck?

Okay...thanks for the replies!
Edelbrock heads, 84 cc. Performer RPM intake, Barry grant 850 VS with 85/90 jets and a 3.5 power valve. 3000 stall converter. MP electronic distributor with vacuum advance. It usually does NOT ping at part throttle with the advance connected. Initial timing is at 17 degrees.
I have heard that quench is lost at anything over .055 inch. My pistons are .017 or .018 in the hole, and the Fel Pro gasket is .039. That means that I am already at the edge of having no quench as it is. If I'm wrong, who has the right info?
Oh, with the 2" TTI headers, checking plugs after a hard run is NOT easy. I've burned my hands enough. Emissions/smog type exhaust testing on a dyno may be the only way to determine the proper carburetor settings.

We are running 11:1 with a similar set-up at 35º and no problems. I run a smaller cam than that so you should be OK. I would really be interested to know what plugs you are running?

You should be NGK 6 or colder or Champion 10 or colder.

Spark plugs.... That subject has come up before. I have used the plugs recomended by Edelbrock: RC12YC. I suppose that the "12" is the heat range? A 10 number would make it a colder plug and therefore LESS prone to detonation?
Whats the downside to running a colder spark plug? The motor has about 1000 miles on it. I doubt that it would oil foul with properly seated rings.

Before you get too involved I am going to say that 12's are way too hot for a true 10.8:1.

Champion 10's may be closer, you will know right away.

We run NGK 6's with 11:1 on the street and 7's for the track.

For you it would be Champ 10's for the street, 9's for the track.

I have read good things about the NGK plugs..... Tell me more!
can anyone explain the science behind the "hot versus cold" plug heat range? Is it correct that the colder plug resists detonation better?

Colder plug resists detonation but if you go to cold it will be prone to fouling... The more compression the colder the plug needs to be...

Its a fine line and sometimes trial and error. The science I may not be able to explain but the coldest plug you can run without fouling the safer it is for the engine especially for higher compression......is there an echo!

Okay. I guess I can try the NGKs and see how she runs. Whats another $20 anyway? If nothing else, I can rule them out if they don't help. Thanks for the help.

I think you will be surprised. Good luck.

A GOOD surprise? Lets hope so!