Your drivetrain is fine, but you might want to add some form of lower gears for more control What does the 700r4 work out to for a crawl ratio? I'm ditching my SM465 for the 700r4 and adding a 203 doubler. The NP205 isn't my favorite tcase but it'll work and the rear is already centered.
For body, take a look at mudrak's bed. He is going to ditch it at some point and go aluminum to reduce pregnant yak effect. The problem with more weight.. is more weight.
What size tires? That should dictate what you do with the suspension but generally 35s should be a working minimum. Do your power steering plates right, 4wdiscs, longfields, should be good to go. Recommend lots of body protection, or something like metaltech tube fenders, a long slider and some exo-like rear protection if you don't flat-bed it.
Minus the tranny and springs setup for weight and not flex, mine is pretty close-
http://130.94.161.162/images/LC/ken/album/
For the rear, the best I can tell is it's a cut down D60 housing (haven't cracked the cover to see what's inside), with cruiser full floater axles. The inner splines have the slightest of twists so it's time to re-figure something back there before they snap. The 454 is built but was tamed a little from a Holley dumper to a Q-jet. I want to put fuel injection and a MegaSquirt controller in.
But the BJ42 is getting my energy over the winter... so FJ454 will have to sit and wait.
