You want it in that swb in your avi?
Go big or go home.
4.6 top hatted block, performance heads & headers, couple that up to a ZF4 & LT230, get the LT 2wd converted, diffs & half shafts, Rover with HD 3.5 ring and pinions & HD shafts, leave drive members std as they're your fusible link, dirt cheap & fast to replace (5x 17mm bolts & a gasket).
Are you 95% road or 99% road & maybe bump the curb?
I ask as you could scrap the V8 & grab a Jag donor & do a full V12 & box installation, rip out the front diff & shafts, put a cover plate on there to save weight & go rear wheel drive easy enough, the Belgian army used to run a fleet of 2wd series many moons ago.
Got some piccies for us to oggle?