how much can i overclock

Solution
The guide says "Core 2 Duo E8400 ~ 3.8-4.0 Ghz stable overclock on Air with Good After Market Heatsink."

and

VGreat overclocking chipsets for motherboards:
Intel P45 Express Chipset by Asus
Intel X48 Chipset by Asus, Foxconn
Nforce 8 and 9 by EVGA (watch out for Nforce northbridge a lot of motherboards dies because overheating the northbridge during good cpu temps.)

Intel X48 Chipset was the last revision of chipset for Core 2 Duo/Quad and considered to be the best and safest Overclocker for the Core 2 Duo or Core 2 Quad.
"
The guide says "Core 2 Duo E8400 ~ 3.8-4.0 Ghz stable overclock on Air with Good After Market Heatsink."

and

VGreat overclocking chipsets for motherboards:
Intel P45 Express Chipset by Asus
Intel X48 Chipset by Asus, Foxconn
Nforce 8 and 9 by EVGA (watch out for Nforce northbridge a lot of motherboards dies because overheating the northbridge during good cpu temps.)

Intel X48 Chipset was the last revision of chipset for Core 2 Duo/Quad and considered to be the best and safest Overclocker for the Core 2 Duo or Core 2 Quad.
"
 
Solution