when i turn my key off my motor stays running its a chevy vortec ho 350 carbed optima battery i have a volvo paris and rhone alternator that has 3 wires on the back one is d+ WHEN I UN PLUG THIS ONE THE MOTOR DIES when i leave it unpluged the alternator doesnt charge but the motor shuts off when the key is off what is wrong its a new battery and alternator

While I cant pinpoint your exact problem, I can say with almost certainty, that the alternator is directly powering your distributors positive lead. You need to trace the wiring and isolate that alternator circuit. Then male sure your distirbutor positive is isolated only to the ignition key.

if you did not change anything and this just started, the diodes in the alt are bad allowing currant to feed back causing the issue, if you changed something then look there..Rob

If you reverse the connections at the alternator, the two small wires, this will happen as one small wire is direct battery reference for the regulator. If you reversed them, you are supplying full time battery to the ignition side of the system.