Re: converting 3 wire alt. to 1 wire alt.
I hope this is in regard to the INTERNALLY REGULATED 3 wire alternators, as the externally regulated alternators also have a 3 wire connect. If the internally regulated alt, I do it the way GM does it, simple.
BATTERY cable to large BATT lug on back of alt
14 gauge jumper wire from BATt terminal on back of alt to side terminal number 2 (Please note, this is the way GM sires tham up, and, there is also a farm and industrial implement regulator for these alternators, those regulators do the same as the external jumper wire, but, INSIDE the alt, and are what the aftermarket builders use).
If you are not running a charge light, done, works
If you are running a charge light, simply connect the charge light to the number 1 terminal, with no other resistor/diode in place, done, light works as stock