Hi, and this is a tutorial on how you can install the Voltz modpack for 1.6.4!
Make sure you have installed the technic launcher and logged in using your minecraft account!
Step one: Go to Voltz and click modpack settings.
Step two: Click Latest under select version.
Step three: Click the X up at the top right corner, that saved the setting, then click play. When you click play, the launcher will Prompt you to get a update. Click yes, and it will update it to Minecraft 1.6.4!
Hope this helped!