Lf Wiring Diagrams '77 Cobra Ii

I don't know of an online resource. What I used was probably the same as you will be using. I had, I think, the Haynes manual and used those diagrams. I took every page that mattered to me and copied them using my scanner/printer so I could write all over them without making my book a mess. Now it's been >10 years since I've messed with my wiring like that, but it seems that the general diagram and my car's harness didn't necessarily match up on every circuit. Also, I had multiple harnesses and found that the body harness had to match the engine harness. I've heard others not have any issue like that, but just something to be aware of if it applies. Like I said, it's been quite a while, so I unfortunately can't help other than giving this advice. Hopefully someone else has more/better info for you.....