Though the oil pans looked...
Though the oil pans looked dimensionally similar at first, there was enough difference that the Mustang pan was swapped onto the 5.4. The 4.6 oil pickup sat 1/2 inch deeper in the pan than that on the 5.4, so it was swapped along with the oil pan.
The 5.4 intake is wider and the factory intakes that are available are far from ideal. The trucks have plenty of room on top of the motors, so Ford makes no attempt to keep the height down. In addition, the throttle bodies are pointed in different directions and sensor locations are different. The E-150 van has a shorter height intake due to its more cramped engine bay, but it is still quite tall. Its long runners are designed to make the kind of torque curve that truck owners appreciate, but that would make sports car owners feel as if-well-they had a truck motor.
After some careful measuring, it was determined prior to this project that the stock 4.6 intake could be reused if some custom adapters were made to allow it to bolt to the wider 5.4. It would all fit (hopefully-since the spouse was told it would) under a stock hood. There are several benefits to this method, the most important being that the fuel rails, the injectors, the sensors, and the throttle body are all in their same relative positions and will require no modification to reconnect them. When it comes to swap simplicity, this is a huge plus.
Being able to physically bolt...
Being able to physically bolt on something doesn't guarantee perfect compatibility. When the 4.6 oil pan was first installed on the 5.4, one of the rod bolts was catching the oil-control baffles in the front of the pan. The longer 4.16 stroke (versus 3.55 on the 4.6) has the rods swinging lower in the pan-in this case, too low. The baffles were simply bent down a quarter of an inch to provide clearance.
Another benefit is that using the same intake as the 4.6 will keep us as close as possible to the initial goal of seeing what power gains the bigger short-block is worth by itself. The P.I. ("performance improved," in Fordspeak) cylinder heads on our 5.4 are identical to those installed on '99-and-up Mustangs, as are the cams. Apparently all P.I.-headed vehicles, whether car or truck (even Lightning), wear the same cams.
We will be using the complete 4.6 exhaust, including headers and stock cat H-pipe. The front of the airpath from the filter through the throttle body will remain unchanged. This gives us as similar a configuration as can be achieved between the two motors, with the notable and regrettable exception that the intake adapters will add approximately 1 3/4 inches of runner length to the 4.6 intake manifold. We say regrettable because the intake will already have a lower peak-power rpm when installed on the larger motor, as compared to what it peaked at on the 4.6, and the additional runner length will lower that peak a bit more. For now, however, this is as equal a comparison as possible, and a shorter runner and higher flowing intake will be tested later on.
Many thanks go out to Brian Ebert at HiTech Motorsport for his help on the project. Without his tuning prowess, our results would not have been nearly as successful-check the dyno charts to see why. Now follow along with the pictures and captions as we go big or go home.
The van that previously held the 5.4 required a relocated oil filter, so the casting that contains the oil-filter mount and lower radiator hose connection was pulled off the 4.6 and installed on the 5.4. The gasket for this (along with most others on the motor) was reused, as the newer-design gaskets with a plastic body and rubber O-rings around the sealing areas do not crush as do older-style gaskets, and can be used many times.
The dipstick tube was reshaped just a bit. A new hole drilled in the bracket allowed it to bolt to the same mounting spot on the head as before. Above the rightmost exhaust port, the head has the letters P.I. cast into it-an easy place to look if you're trying to determine whether or not a potential donor has the newer motor.
While both motors were out and acces-sible, the cams were measured to make sure they were the same. Both measured at 0.282 intake and 0.297 exhaust lobe lift, or 0.508/0.535 max lift at the valve. All P.I.-headed modulars, whether car, truck, or van, reportedly have the same cams, so you shouldn't have to worry about swapping the Mustang cams.