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Discussion Starter #1
My '68 Camaro 350 wiring is a mess. Can anyone tell me the correct (or best) wiring for the Negative Battery Cable. Does it connect on the inner fender, the alternator bracket, the engine block, or what? Also, where does the pigtail connect to ground? I see several conflicting posts on this topic. I actually have a later model alternator bracket on the car with a threaded hole and it seems like in later years they moved the ground to that location. Is there a reason for that? Was the bracket found to be the better location (maybe better for the alternator to function)? Thanks
 

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I can’t help with factory correct but the best would be to the case of the alternator for charging and to the starter case for starting. The reason for that would be less connections to go through before it got to the negative terminal on the battery (the reverse would be a straight connection from the battery positive to the alternators output post and a straight connection between the battery positive post and the starter motor). Let’s say we move the ground from the case of the alternator to one of it’s mounting bracket. The connection now has to come out of the case of the alternator, make an electrical connection to the bracket and then another connection to the cable end. Most brackets have thin paint on them that is broken through when the mounting bolts are tightened however if the bracket has a thicker layer or harder layer of paint or powder coating on it the mounting bolts may not break through and make a good electrical connection.
The pigtail off of the negative battery terminal goes to the chassis of the car. This can be a fender or radiator support (also take into account or be aware of that sometimes the fenders or radiator support have been painted off of the car and may not make good electrical connections through their mounting bolts when reinstalled back onto the car). If we never upgrade this wire to a larger size or add other cabling between the block and chassis of the car this is the limiting return path back to the battery. The factory only makes this wire large enough to handle what they have designed for the car. If you add a stereo amplifier that requires a 4 gauge to power it then you must add a 4 gauge ground wire between the battery negative terminal and the chassis of the car (providing the amp is grounded to the chassis of the car). There are other ground connections between the engine and the chassis of the car and these include the emergency brake cables and shifter cable. If the main ground on the block or the pigtail starts to become a restriction then those cables can become welded together from them trying to pass the current through them.
When I do battery connections I clean the area where the wire terminal end will be attached at and then use a star washers between the terminal end and the mounting surface and tighten the bolt securely. If it is in an area exposed to moisture and water, I cover the connection with silicone to slow down the corrosion process. On my mid 70’s Chevrolets I have always used the hole on the top alternator bracket and not had a problem and had the pigtail on the inner side of the fender.
On customer's cars where I've installed a high output alternator there is a threaded hole in them for easy attachement of a ground cable that then goes to the battery's negative terminal. If it's there, use it.
Jim
 

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The hole in the alt bracket is for the ground cable from the battery. Some GM cars were grounded on the block some on the the bolt on the thermostat housing and some on the alt bracket. What is correct depends on year and model but all 3 will interchange and function. The small pig tail off the ground cable is bolted to the panel above the inner fender near where the fender brace is attached.
 

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The heavy cable goes to the block or alternator bracket. It really doesn't matter. Then the short pig-tail attaches to the fender. The fender ground provides a return path for lights, radio, and other accessories. The block provides a return path for the starter, ignition system, and alternator. The reason for two paths is to try and reduce interferance with the radio.

If you're looking for cables, check out this post. http://www.camaros.net/cgi-bin/forum/ultimatebb.cgi/topic/10/2741.html?
 

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I posted a pic of my setup on image station. It is a 327 without air. You can easily see the heavy gage battery cable goes to the water pump. It is put on the stud with an additional nut and star washer. The pigtail wire is connected to the fender bolt via an eye connector. In the picture you can see the yellow splice connector and sort of make out the wire going to the fender.

http://www.imagestation.com/album/?id=4285869993
 

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Discussion Starter #7
Thank you all very much for the information. It makes sense to me now how the return path of the electricity through the ground needs to mirror the Positive connections. My existing configuration has the large negative ground cable from the battery connected via a fender bolt screwed into the inner fender well below the battery. This is not a good setup, especially for the starter motor when cranking. I will move the ground connection to either the alternator bracket or a block connection bolt (waterneck or pump) making sure that there is a clean contact with no paint insulating the connection. I really appreciate the willingness of everyone on this site to lend their expertise and knowledge, including the picture post from M Ryan. It makes the hobby of restoring the car that much more enjoyable when you have a group of helpful people that contribute their expertise directly into your car!
 
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