First off, thanks for everyone's response. And, please don't get me wrong, I'm very familiar with the strength benefits of my current setup and I've been running this for the past 4 years with no probs other than the throwout bearing actually pushing through the clutch and jamming in between the pressure plates. What a mess that was and it happened about 9500ft and I had to crunch gears to get it back to denver without stopping! If I was towing with it or used it for strictly 4wheeling, I would not even be considering the swap. But now that I use the truck for more daily driving and camping/skiing excursions, the auto would be a much smoother ride. From the research I can find, a TH400 would work, but I'd much rather have the lower first gear and overdrive of the 700R4 and so people say that if built right it could handle my 500+hp big block. My only reserve is that the 465 is basically brand new, and the conversion parts to mate the 205 plus the cost of 700R4 and cooling system is adding up $$ fast.
I'm not dead set on this conversion yet hince the reason for the post, but again, I appreciate everyone's input. If anyone's running a 454/700R4/205, I would like to hear what you think of the combo, and durability. And if I decide to do the swap, I'll let you know how much I want for the sm465. Thanks again!