Try turning up some voltages, say up the CPU and RAM by +0.05V. I could only increase the FSB on my 1700+ by a very small amount until I raised the CPU voltage to 1.85V, even then I could only raise the FSB to 144.
I had the most success by unlocking the multiplier, at CPU & RAM at +0.1V I was able to get up to 10x158.