Change starter in 2001 cad devile

The starter on that engine is mounted between the cylinder heads under the intake manifold. You will need a set of injector O-rings and an intake manifold gasket set to do the job. It is not really hard to do, but a bunch of stuff has to come loose to get the manifold off.
HINT: The gasket surfaces for the intake manifold are very easy to clean up in preparation of re-installing the manifold if you use some rags and carburetor cleaner.