Are you planning to build this to be a trail rig along with your Rubicon or is it just going to be a mall crawler? I love the sound of the big V8s, but the practical side of me says add fuel injection to the 4.2L and gear it the way you want and it will be a much more economical vehicle. Or take the drivetrain out of an XJ for the 4.0 with FI. Either way, Scramblers in that condition are getting hard to find and you'll have a blast with it.