Honestly, I'd keep it under 1100 for long periods. It's not melting aluminum that's the problem - the pistons are cooled by oil jets from below.
The more likely failure is a valve having issues.
Not to mention, you really don't get more power anyway. You are limited by the air going in, and that air can either burn with carbon, or if you give it a 'rich' mixture, it'll burn with hydrogens in the hydrocarbons, and just leave soot(carbon) behind. Hense the smoke.
In my experience, go for a turbo. You can then literally max out the pump, and burn it all cleanly, while keeping your EGTs sane(leaner burn).
Because you can burn more fuel, you get more power. A *lot* more power, especially from 2k-3k RPM.