Thanks for the reply. Much appreciated!
I was over a friends house last night who happened to have a TH400 lying around. We checked it for the clip and lo and behold there was one on it! Now, I'm not 100% certain it's correct but I've searched the web high and low and have come up completely empty on what this darn clip is suppose to look like. He was kind enough to give me both the clip and screw, which BTW is another tough one to find! It happens to be the same screw that secures the fuel tank sending unit ground wire to frame rail but it's a real odd size that neither AMK or no else for that matter, offers.
So until I can confirm what the clip actually looks like I'm going to run with what I now have. It'll be a while before the engine and tranny are in the car so my hunt continues.
BTW...My car does not have AC.
Once again, thanks for the reply.