85 cutlass electrical problem

i have a 1985 olds cutlass supreme brougham and i just recently changed the engine in it. when i finished installing the engine, i was able to crank it, then i ran into a problem, the alternator was bad, so i changed it along with the battery. since then i've been through about 3 or 4 alternators and batteries. when i put the new ones in there it will crank up, but whenever i kill the engine, it won't crank up without a boost. i have some extra wires that are not being used because i replaced the factory carb with an edelbrock 500cfm. could it be the bundle of wires that are not in use that's causing the problem??? please help....Thanks ahead of time!!!!!