If you put a new 68000 in, and exactly doubled the clock frequency (14Mhz instead of 7), it might just work. Although your PAL output would be 30Khz instead of 15Khz, so you'd need a very forgiving VGA monitor.
Not a chance. It will never work this way.
You need to double the cpu clock while keeping rest of the clock signals untouched. See aminet hard/hack for instructions how to do this on A500 (it's quite easy since the 14MHz clock signal is available directly IIRC). In theory it might be possible to apply this hack to A600 aswell.
This is not overclocking the chipset itself though.
