I have been looking locally for the correct double barrel crimp glow plug connector. I went to Autozone, Carquest, Radio Shack, etc with no luck - I happened to see a Chevrolet dealership and I thought, what the heck, why not. I went in and asked for a glow plug connector for a 1984 Chevy K30 with a 6.2L J code diesel.
I understood that I was in a dealership, but I was blown away by what they said. Part # 15320904, which is the glow plug connector terminal is $67.84 per. About $593 after tax for 8 glow plug connectors. I said almost $600 would buy thousands of them, not 8. The guy kinda shrugged.
Wow!
I did find them and order them this morning from O'Reilly's. I think they're hard to find because the double barrel crimp is not a "consumer" level item for the most part.
On a side note, Radio Shack used to be cool. Now its just phones, computers, and crappy RC boats. They have to know your address, life story, and names of your kids just to sell you something and act like its not weird to ask those things.