Board Thread:General Discussion/@comment-85.27.36.211-20140209231456/@comment-24529259-20140210114658

I'm not too sure of what you are asking here, but I think I know what you mean.

It is not possible to add RedPower2 Pre6 to Tekkit Classic. Tekkit Classic is for Minecraft 1.2.5, whilst RedPower2 Pre6 is for Minecraft 1.4.6. If you want to play RedPower2 Pre6, you will have to use Minecraft 1.4.6.

To answer your question: No, it is not possible.