Just my two cents, but best bucks down approach is find a good 5.9 magnum motor and install it. Use the exhaust manifolds that come with it. Get a crosswind intake and use your Qjet. If you are going to drive it much, I would also think about putting a 518 trans in it. It is a direct bolt in using a trans xmember from a 90-93 D150 that came with that trans. These are the two best bucks down improvements you could make for
power and economy. For about $150 more you can get a reground cam for the 5.9 as well.