"...it deserves an easy life from this point forward." I couldn't agree more.
I like the 350, plenty of power and plenty of parts at a reasonable cost.
There are several ways to go with the rear. You can have a Ford 9" or 8" built to match your width etc. Or you can go the cheap (inexpensive) route and shop the bone yards. GM made several rears that will fit, I have a 10 bolt Camaro. Someone posted a printout of different differential sizes somewhere here today or yesterday.
I would suggest a 700R4 tranny with overdrive and gears in the mid to high 3s.
