GM-GMC: Suburban Starting Problems, connecting jumper cables, ground cables

Question
Hello Mr.Jacobson, thank you so much for your time. I have an 87 Chevy Suburban with a 350 engine that was put in about six months ago by a couple of my neighbors. Everything has been fine except that about once a month I can't start it. For about the first three months I was getting the starters from Autozone, they'd fail and I'd exchange them. Then I started getting them from Napa and the same thing occured. At the moment it won't start again, I took the starter back up to Napa, they tested it and it's fine. I put the battery on a charger and it was fine. The mechanic who put the engine in tested the alternator and said it was fine. When I try to start it, there is a rapid clicking sound and occassionally the engine will turn over very slowly but not start. If I try it again, I get only the rapid clicking sound. The last time I took the starter out (when Napa said it was fine) I put it back in and it started right up, though an hour later it failed to start again. And this happens about once a month. I have been stranded more times than I can count because of this, once with my infant son. Please, any help or advice you can offer will be greatly appreciated. Best regards, Patryck Jordan

Answer
I think that your neighbors failed to install the ground cables that should be on the engine and transmission, or perhaps left them loose.
Exactly where they should be on your application, I cannot say.  But there should be at least one heavy gauge ground wire from the engine block to the frame and one connected to the transmission.  If they cannot be found, they need to be installed.
If all the heavy wires are in place, they need to be checked for corrosion.  Battery cables are known to corrode underneath their insulation.
The end at the starter can be damaged by letting the starter "hang" on it while trying to bolt it in.
If you can get to the large terminal on the solenoid, and I know that it is difficult on GM V-8s, you can try connecting jumper cables to see if the starter will work by bypassing the vehicle's wiring (connect the ground end to the engine block and the other end of the jumper cables directly to the battery).  If the starter cranks the engine normally (using the key in the ignition switch), try moving the ground connection to the frame and repeat the test.  You may find that you have a missing ground wire or a bad battery/starter cable.
Always be CAREFUL working around the battery.  Hydrogen gas will explode when it has oxygen and a spark present.  Also, be certain that you do not ground out the jumper cable lead going to the large terminal on the solenoid before you make any connections to the battery.