The 24MHz runs fine. 30MHz however will not. The chip is rated to 20MHz, not 16.
I've overclocked PC CPU's since the late 80's, 20-25% extra is normal. I'd read that it cuts chip life to 3-5 years but that was when in 3 years there would be 1 or 2 new chip generations out. My 286 would burn out by the time I was running a 486. So how much worry did I have? None at all.
I guess that you know the write to the PINn register bits to toggle the PORTn bits trick? I love that little cycle-saver!