I just finished my project of installing 5.9 magnum manifolds into my 65 dart running a 340, 904LA automatic floor shift transmission. I did a lot of research on this site, did a lot of trial and error and here is exactly what I used to make these manifolds work in my car. 5.9 magnum manifolds off of a 98 Dodge Durango. manual steering box to a power steering shaft with this coupler. Ensun 3/4-36 Spline x 34 smooth.(see pic) 3 1/8 thick washers to shim driver side motor mount. here’s how I did it. First off when I bought my manifolds the salvage yard had cut the exhaust pipes which left me about 6 inches of pipe on either manifold. This helps tremendously. Passenger side of the motor, remove all studs from the head. You have to use bolts for all six holes on the manifold in order for it to slide in. That was the easy part. Driver side, first I use the three 1/8 inch thick washers to shim under the driver side motor mount. So that I did not have to remove the entire mount I cut a groove in the washers so that I could lift the motor just high enough and slide them around the mount stud. I had a power steering box so I remove that and put in a manual stock steering box. Then I ordered the above coupler which fit perfectly between the steering box and my Power steering shaft. What I had to do in order to attach the Cupler to the steering shaft was: pull out the steering column, press out the pin that runs through the steering shaft, slide the coupler on and mark the hole to be drilled through the coupler. I drilled one side of the coupler and then put the shaft back in to line the hole up perfectly while I drilled through the other side of the coupler. I pressed the pin back through and then reinstalled the steering column and attached it to the steering box. This fits perfect once the engine is shimmed up three eights of an inch. I also cut off about 3 inches of the housing of the steering column. You have to do this in order for it not to hit the manifold. With both manifolds on and everything tighten back up I personally chose to use 2 inch flexible exhaust repair pipes that were about 18 inches long. I use these to attach to the 6 inch piece of exhaust on the manifold and bend it to fit down through the torsion bar and next to the transmission. I then purchased two pieces of exhaust stock which I attached to the end of the flexible exhaust piece and that went into the Flowmaster delta 40 mufflers. I fabricated my own hardware to hang the mufflers. I also had to modify the passenger side of the transmission mount to allow for the exhaust pipe to come straight back through.