Thanks for the reply's I managed to get the following oc's
Both with 30min Prime95 Blend test pass
4200Mhz 17.5 x 240 CPU 1.55v NB 1.30v Ram 1600Mhz @ 1T-9-11-11-Auto
4191Mhz 16.5 x 254 CPU 1.60v NB 1.35v Ram 1355Mhz @ 2T-11-12-12-Auto
I managed to get above 240FSB when I set the ram timings above instead of using the Auto setting.
Anything above 255FSB won't boot no mater what volts I use. So I have settled for 4200Mhz 17.5 x 240 for daily use, due to less heat than the 4191Mhz 16.5 x 254 overclock.
Thanks for the posts and help