I guess it's safe to assume you've considered the work involved in "dropping in" a new box, changing/fabbing a new pitman arm and modifying the stock or changing the column, shift linkage and electrical. As Waldo53 correctly points out, swapping out a set of Rams Horn headers would be the least painful solution. Headers in general, don't factor in until you get way up in the rpm range.
If you were going to go for a power conversion you'd have to make these changes. I prefer the stock manual box in my daily driver 54 as it is tough, responsive and I get good feedback from various road surfaces. Consider the Ram's Horns...and you'll save yourself a bunch of headaches.
Dave
BTW.....if you need additional clearance you can use a pass side truck Ram Horn exhaust manifold with the outlet pointed forward on the Driver's side.
Dave
