Shown here are the nearly completed adapters installed on the 5.4, with some of the bolt holes yet to be drilled and tapped. You can see on the top adapter that the coil packs stay in their original location and will now bolt to the adapter. The fuel injectors stay in the intake manifold as before. With the adapters in place, any 4.6 manifold will bolt right on, giving us the flexibility to make a future change without having to wait for a company to come out with a 5.4-specific Two-Valve intake.
Here is the 4.6 intake installed on the 5.4 with the custom adapters. The air and water passages angle through the adapters to bring them into alignment with the narrower 4.6 intake manifold. The adapters first bolt to the heads with recessed-cap head bolts, and the intake then bolts to the adapters. After many hours on the mill, it was a good feeling to put it all together for the first time and have everything line up perfectly!
The 4.6 flexplate had a slightly smaller-diameter torque converter bolt pattern, and was swapped onto the 5.4. Because engine balancing is not done with the flexplate, they are interchangeable as long as you have an eight-bolt Windsor 4.6 and not a six-bolt Romeo. In this case, it would have been nice to notice the slight difference in bolt pattern while the motor was still out of the car, rather than while reinstalling the transmission (the first time).
Due to the extra 1.6-inch width, installation was quite a challenge with the A/C lines on one side, the brake booster on the other, and the ABS module in front. Repositioning the hoist to tilt up the front of the motor finally allowed it to slip in, but it would have been advantageous to have a hoist with tilt capability for this installation.
Once the 5.4 was set into place, there was plenty of clearance everywhere except for the passenger-side header. The header's casting had a lump on the outside that had nothing to do with its function. The lump was touching the framerail and needed to be removed. Jacking up that side of the motor a bit allowed us to grind off the lump, with the motor in the car. Once this was done, there was approximately 3/8 inch clearance to the framerail. This operation would be much easier to do beforehand on the engine stand.
The 5.4 is approximately 0.8 inch wider on each side, and the cylinder heads sit 0.8 inch higher than before. This means we'll need a wider H-pipe. It also means the exhaust is being pulled closer to the floorpan.