i've got an 80 trans am with a 403 olds swapped into it and its run fine for about 2 years the way it is. basically the battery cable is run to the starter and the ground to the block. and its had a live wire off the positive cable running to the back of the alternator. recently i brought it to the shop cause i fried brand new cables in it and they're telling me im basically hotwiring my car everytime i start it and they have to redo my entire wiring system cause it shouldnt run to the alternator from the battery. any help?  

wiskas, since all GM engines of this time period are wired basically the same, I'll outline what should go where. First your primary cables from the battery, the negative should go to either the engine block/head or to a bracket on the motor (ie: alternator bracket on a 305/350 Chevy). The Positive cable goes to the large post on the starter. There should also be a ground strap running from the block/head to the body, usually near the heater box or wiper motor, and sometimes one from the battery neg to the fender or rad support. The alternator has three wires, one (8 or 10 guage,red or dark pink with a ring terminal) goes either to the large post on the starter or to the battery positive. That is the circuit that charges the battery. The other 8/10 guage red or pink wire goes to the 2-wire plug for the voltage regulator and supplies battery voltage to the regulator. It is usually connected to the same point as the charging wire and both are protected by an inline "fusible link" which is a thin fuse wire in the circuit. The other wire in the 2-wire plug is the "exciter" wire for the regulator, it is powered by the ignition switch so the regulator knows when to start charging (usually white or black and about 14guage wire). Where the two 8/10 guage wires are connected (either the battery positive, alt positive or starter positive post) there will be another large guage wire, with a fusible link that feeds the rest of the electrical system, it goes to the fuse panel harness plug under the brake booster. The remaining wires are the pink HEI ignition power, green temp sensor wire, brown or black tach lead for the HEI and wires for oil pressure switch, electric choke(if equipped) and A/C (if equipped). On cars that had Chevy engines the 3 large guage red wires usually go to the starter positive post and get their power there, with the alt wires running along the right valve cover to the alt and the main power feed going over the top of the bell housing to the fuse panel plug under the booster. Some Pontiac equipped cars, such as my 79 Formula, had the power wire running from the battery cable to the alt positive post and then the fusible link wires hooked to that.
I suspect someone may have cut out a fusible link at some time and replaced it with a splice of regular wire, now if you get a short or excessive current draw, the wires melt instead of the link. Hope I've helped.
Steve  

well the way the shop had hooked it up and the way it is now is the fusible link wires (both of them) are hooked at the battery terminal. my main question is that they said essentially i was hot-wiring my car by having the two fusible link wires, the battery wire and the exciter hooked into the post on the rear of the alternator, is that true? or is that how it should be set-up? it seemed to run fine with that set-up.  

The way you are describing it sounds fine, but if you would like, take a pic and e-mail it to me at barneybigrig70@yahoo.ca  
Steve