Those terminals can be found at any GM dealer if you do the work to find the part number. You can also find connectors, pins, terminals, etc at Delphi’s automotive connector page
http://connectors.delphi.com/DCSGDMCS/HomePage.aspx then order them from
http://www.mouser.com/delphi/.
Download the 404 page catalog (19 MB) while you are Delphi’s page as it is an invaluable resource when doing GM powertrain swaps. With this catalog you will be further ahead than most GM dealer parts counter folks. Electrical terminals scare dealer parts people for some reason as they actually have to “l@@k” up the correct parts instead of getting the numbers easily from the GM parts catalogs.
The hardest part is identifying the proper terminal size as there have been a few difference sizes used over the years. I recommend purchasing the special crimper too.