Jim Willy, who posts on this site, has a v8 auto in his series.
One problem you have is that the front axle, having UJ's instead of CV joints isn't designed to take full time 4wd. You could swap it for a stage 1 front axle (read hens teeth and lots of cash) or I'm not sure if Ashcrofts kit to fit a 5 speed manual to a series transfer box will work with an auto, also quite a bit of cash.