Well I suppose I should update this a little bit. Pulled the old 406 sbc out before the winter. Stripped the 5.3 down to its bare essentials.
I grabbed a 4L80 flexplate and spacer, nothing else should be needed to bolt the TH400 to the LSx engine.
Also spent some time figuring out how I was going to drop the engine into the chassis. Saw some bolt on adapter mounts online and the light bulb went off in my head. Decided to build my own, after taking all the measurements heres what I came up with. After bolting them on and measuring bolt locations its within 1/16" of stock location.
The next step was figuring out how to get the car back on the ground after the rearend was sold. Talked to John (MY84z) and he was looking to sell the Moser 9" again. So I bought it back
Then I realized I needed some LCA's and PHB again, found some mint Wolfe ones for sale, bought em, and waited and waited.. never showed up. Went through a big hassle but the guy eventually sent my money back. Found some UMI ones on ls1tech and grabbed em!
As of now the swap and everything has been stalled with the crappy weather and the car being in a non heated garage. Hopefully get everything settled in soon!