[PLUG] git and other version control at the same time

[Larry Brigman]

I have the responsibility to maintain a kernel for a product we are building.
I would like to use git to allow me to pull code in from kernel.org
without having to
search for patches.

I have two issues that seem to be at odds of doing what I want.
1) I started with a tarball not a git clone.
2) I have to maintain a checked in version of source code in Clearcase

As anyone has some experience in dealing with a situation like this?
Recommendation other than chucking Clearcase?