Wow! I'm really impressed with these options and suggestions.
And Scotty, I apologize - for some reason I though you were up in Portland but when you live in Kentucky anything west of the Mississippi is the West Coast. You took a stock Ford points type distributor and made it into an electronic ignition. Works great and it looks stock. So basically I wanted everything on this engine to look stock from the outside.
Lem Evans designed my engine for me, and he provided me with all the parts (except for the block and some other external parts). He was actually a little embarrassed because it only produced 572 HP, while he's used to getting more like 750 or 800 HP. But I wanted a smooth running engine that sounded stock. We put a full glass of good ole Kentucky Bourbon on the shaker while it was running and never spilled a drop. We did this about 5 or 7 years ago but I dropped out of the muscle car interest due to the unexpected death of my 23 yo son, which you can imagine will put a sudden stop to any plans. So now I'm ready to put my toe in the water again. Anyway, I have 4 other DOVE-A blocks and a bunch of heads, intakes, etc. Have a bunch of nodular rears with 31 splines as well.
This first application is the 429 in the 71 convertible. Per the reply from Mark G, I've studied the Overdrive mechanism from Gear Vendors and it seems to be incredibly durable and well though out. I would rather go with a dedicated AOD by Ford or keep my original C6 though. I don't think I like the idea of pushing buttons to make it shift through the split gears. And as per r72cnvt who suggested a 3:25 or 3:50 with a C6, I've done a lot of hand calculations and come up with 3:18 as the optimal gear ratio if I keep the C6 with this engine HP and Torque.
And thanks rattle_snake and jpierce55 for your inputs as well. Basically I think the option of the E4OD is out (too big) and the AOD is out (not durable enough). I don't like the Gear Vendors option b/c I have to put a ton of money into my C6 as it hasn't seen any action for 30 years, and then I would have to spend another $3K at Gear Vendors for their device. So, I'm thinking about the JW Performance Ultra Bell bell housing with a performance built 4R70W or something similar. Or just keep my C6 with a 3.18 or 3.00 rear end. This engine has a large amount of torque and a very flat torque curve from about 2500 to 4800 rpm, so a you say, will easily handle the conservative gear ratio.
Anyway, if anyone is interested, I'll keep you posted. Sorry for the long PhD dissertation. My next build will definitely not be stock, and I will send my heads up to the Mad Porter, somewhere out in California, or wherever the hell it is, Washington DC? Portland Maine? to get the works.