TH400 to 700R4 Swap - Need the Low-Down

[Chevy00]

I'm planning to swap out the TH400 in my '69 LWB w/ SBC power. Although I know I need a 700 for the Chev pattern, what will I need to be prepared for during the process. I've read so many articles & some contradict one another - I'm looking for help from someone who has made the swap successfully. Also, I've heard there is a mechanism to eliminate the toggle switch to lock the torque converter - Where can I find one?

Thanks in advance -