Looks like you're using Pokenguyen's guide for both Hacks.
For E7440, the audio kext = AppleHDAALC.kext
For E6430, the audio kext = AppleHDAIDT.kext
Both found in /System/Library/Extensions
You could do it 2 ways. Either use mine pre-prepared kexts or update them yourself.
1) For E7440, Find in Update section, download AppleHDA_ALC292, rename it to AppleHDAALC and overwrite it in /S/L/E with kextwizard
For E6430, download AppleHDA_IDT and rename it to AppleHDAIDT.kext and overwrite it to /S/L/E with kextwizard
2) Follow guide here. Editing the 2 kexts mentioned