The short answer is yes, it'll bolt up and work just dandy. The longer answer is yes, it'll work just fine but while you have the H.O. engine out and it's easy to work on you might want to consider changing the cam (and of course the lifters as well). The stock H.O. engines are tuned for horsepower over torque, pulling the cam & replacing it with an RV type cam will give you an engine setup for a truck and not a Mustang. It'll work either way but swapping cams will really make that engine shine when you drop it into the truck and if it's a late-model engine with the roller cam you can *really* take advantage of the opportunity. Run yourself a real torquemonster cam AND swap out the rocker arms for a set with a better ratio and it'll be a completely different animal than if you'd installed it without changing anything. The stock cam has a powerband & torquecurve that's all wrong for a 4000lb truck with the transmission & gearing that you have, but like I said, it'll work regardless of what you do (or don't do) to the engine