After having recently found some of the wires to my alternator broken off at the very back of the plug, I've been looking for replacement or repair parts, & have found a few. Will fit 1972 to 1978 Pickups; may fit some pickups from 1979-1984. Here they are:

http://www.globalsoftware-inc.com/co...Connectors.htm

Part # 3P786.3. This is the tricky way to do it. You crimp on new female spade lugs to your wires, then push them thru the back of the new plug; they click in place in the plug. MAKE SURE YOU PUT THE RIGHT COLORED WIRE IN THE RIGHT PLACES ON THE PLUG OR IT'S DISASTER TIME!

http://www.repairconnector.com/produ...or-3-Wire.html

Pigtail type; just splice it into your existing wires. Solder splicing recommended, but you could use butt crimp connectors.
Blue & Green wire positions on plug are correct; Red wire matches up with White wire.

http://store.alternatorparts.com/c16...connector.aspx

More expensive but a little less hassle; butt connectors already on the wires. this item appears to be USA made by a company called JIMCO.

If you have the later plug type, where the single port is offset to one side, the last two places have those as well.