Alternator Tach Lead?
 

Hi All;
I had a alternator lead installed on my stock 89 many moons ago 189K miles .. well it is time for a new alt ... I have looked high and low on instructions on how to do this lead to no avail ... could any of you give me a link or instructions on how to ... or do I have to take it to a shop ? I understand it isn't hard to do but nothing is if you have the knowledge. Any help in this would sure be appreciated.

Thanks! Ken