If youre keeping the ivac I would check out the Supercharged section of the KA-T.org forums. You can do this one of two ways. One is to make provisions in your mounting plate (holes or a cut out) so it will mount much like it does to the stock intake manifold now. The other is to find a spot to mount your ivac and run vacuum lines to it. I've seen SC applications that have done both these and worked well.

I agree that it would be worth your wild to keep it...save you motor in the long run.