Who's got toluene experience? I've never run it but have access to it. Does it raise octane or is it oxygenated?
any dyno experience?

Other things that you can do to prevent detonation include, getting cooler air to the carb, a scoop or something. Lower your water temps. If you have fairly wide piston clearence, you can run without a thermostat or with a 120 deg. from Arizona Speed and Marine. Less ignition timing, but be careful, below 30 and your exhaust valves will start to heat up negating any benefit. Richer fuel mixture. Ever take a sparkplug out of a carbed Mercruiser? They are always dark. Much richer than a street car or a drag racer. Good luck.

I run a conservative 33º total timing with 10:1 compression, Aluminum heads, and 93 octane. I can go with more timing for sure, engine builder says another 2 or 3º, but how much hp would that actually gain?

I dont plan to add more timing, as I would rather have it live than eat itself alive, just wondering how much I am leaving on the table. The engine is a 598ci N/A, 10:1, Dart Pro 1 345cc heads worked over, Dominator 1050cfm, Comp hydraulic roller cam .647/.647 252/262 112LSA. Has a crossover with no thermostat. Should be right around 725hp right now based on speeds.

I agree with your engine builder. You're set up pretty conservative. That cam is bleeding off some compression also. Try it and find out.

That is the thing, I know I can run more timing, but for what gain? 10hp with 3º or 50hp? Then i run the risk of getting bad gas and burning up a piston or two.

I am just wondering if there is any real benefit to be gained.

I have very similar engines, same size, compression etc. I am at 32 degrees total advance.

We can't get 93 here. Engines were tuned on a dyno with 92 which is no longer readily avalible.

I add 5 gallons of toluene to each 100 gallon tank at fill up as a safety precaution. Any more octane, and I am loosing energy since I only have 10;1 compression.