We put our starters in the rear of an MC9 on the pass. side where the compressor used to be.
I built a level platform on the top of the old comp. mount. All I did was to hook another line to the rear "hot post". I just pulled the cables and allowed the front switch in the old battery bay to remain operational.(for the lights and such) I put in a new shutoff in front of the two new group 31 starter batteries in the rear access compartment and built cables to hook up to that stud forward of your starter. I also have an isolator in the system to allow my house batteries to charge from the alternator as well.
Hope I explained it well.
P.S. I had some 8D starter batteries explode on me which is why I chose group 31's. smaller bomb!