Re: Starter wire routing.
My positive battery cable comes down from the battery, across the passenger side engine mount, along the oil pan and to the starter (i.e. factory routing pretty much.)
I just re-routed the power to the fuse box direct to the battery instead of having the fusible link at the starter. So, the only wire I have going to the starter other than the battery cable is the ignition switch trigger wire. I decided to route that over to the alternator along the same path as the alternator feed, then down the block to just above the fuel pump, and then run it alongside the battery cable back to the starter. I have no more wires going down the firewall to the back of the engine anymore.
(Note that mine is a '72, passenger side alternator.)
Here's a picture of it partially assembled (once it is the rest of the way assembled I can post a picture if you need it.) The purple wire is the igniton switch to the starter wire (just wasn't run yet, waiting to install the rest of the parts then run the wire.) All the wiring to the engine comes down through the conduit along the passenger valve cover. Trans temp gauge, water temp gauge, alternator feed, alternator regulator, electric choke, starter, main power feed, etc. are all in there. Main power wire runs to the battery alongside the negative battery cable that connects to the alternator bracket, then just drops down to connect to positive battery post (again, not shown in this picture, but it's the big red wire.)
1972 Chevelle, MJ 467, 200-4r non-lockup, 12 bolt 3.73
1981 Camaro Z28, 355, TH350, 3.73