Part 2—From Short-Block To Road Ready

After getting the remanufactured 7.3L short-block and heads back from L&R Automotive, John Ferguson and his team at Domestic Diesel in Chino, California, began reassembling the engine and getting the project shop truck up and running.


The prospect of a shop truck with some reliability and performance was intriguing. Ferguson decided to go the extra mile and add a little more power and make other improvements.

When the truck was acquired, it already had a few things done to it, such as a Banks Power Elbow kit, and the ECM had some tuning done to it too. Of course, these were retained and other upgrades were added to the mix.

An Applied Performance turbo that complemented the previously existing mild upgrades, but didn’t need a lot of extra fuel, was installed. In addition, some fuel system delivery improvers from Riffraff Diesel were selected. While not needed for this mostly stock engine, an FRx fuel rail crossover from Riffraff was installed. This was to improve the idle, making it quieter and smoother, as well as offering better throttle response over stock. A new air intake from S&B filters was also installed to further improve power. This new and improved setup is superior to stock and the original S&B design for the 7.3L trucks.

Other upgrades included a larger intercooler and transmission cooler from a 6.0L Power Stroke. A new 190-amp alternator from DC Power was acquired to improve battery life in this shop truck. This unit has a higher output at idle than stock. A high at idle output is needed on a truck that will do a lot of low-speed, stop and go driving, as this one will while running around town, getting parts for the shop.

Once the new remanufactured engine was in and all buttoned up, it started the first time. We expected no less, and were not surprised. The better than factory 7.3L Ford (International) V-8 diesel is sure to offer years or service. With a little upholstery and a paint job, this truck will be better than new all around. DW


1 Once the short-block was back at Domestic Diesel, it was time to begin the assembly of the engine. First, the rear main seal was installed and then the engine was put on the assembly stand. The oil pickup and pan were then installed.

2 With the engine upside down, the front cover and a new Alliant Power water pump are installed. With the front cover and water pump in place, the engine oil pump was bolted on. This is not to be confused with the high-pressure oil pump (HPOP). The HPOP is actually the oil pump that feeds the injectors and sits on the top of the engine in the valley.

3 Before rolling the block right side up to build the upper end, the oil cooler/oil filter mount is installed. Be sure to check your cooler and replace it if needed.

4 With the pan and other lower end details handled, the block is rolled over. First, the dowel pins are installed in the block deck and then the heads are installed.

5A & 5B ARP head studs are installed in the block and then the head gaskets are slipped down over the studs, before the heads are installed.

6 With the heads on the block, the ARP stud nuts are torqued down to spec. This can be difficult with the engine on a rolling stand. A helping hand to keep the stand from rolling, while cinching down the bolts, is recommended.

7 Be sure that the injector cups are replaced in the heads. This ensures that the injectors have a good seal and won’t leak. The old cups can be removed with the heads on, and the new cups can be installed this way too, with the correct tools. The cups used here are Alliant Power P/N AP63411.

8 New injectors were installed in the motor. With the original engine in the truck having quite high mileage, this was the best option to prevent issues down the road.

9 With the new injectors installed, the lifters, pushrods and rocker arms are installed. Mounting hardware was then torqued to spec.

10 The injectors are connected to the harness (which is also the valve cover gasket on the 7.3L) and the valve covers can then be installed.

11 An important item to replace when this deep inside your 7.3L is the IPR, a.k.a. injection pressure regulator. The shiny new gold-colored item seen here is the IPR. This is an OEM-quality replacement from Alliant Power. This is their part number AP6402 and is a
direct replacement for Ford P/N’s F81Z9C968AA/AB.

12 The 7.3L uses high-pressure oil to inject fuel, at a much higher pressure, into the combustion chamber. The high-pressure oil is supplied by the HPOP (being installed here). If there’s any question as to the status of your used pump, replace it now. This unit had been installed only a few thousand miles before the engine rebuild and was reused.

13 The fuel filter housing is not something you would think of as a critical part. It does, however, contain a fuel heater and when this shorts out, the ECM fuse will blow. Be sure to inspect the heater wires and replace as needed. Also, be sure to install a new fuel filter drain valve.

14A & 14B Here you see the FRx fuel rail crossover from Riffraff Diesel Performance. This part is said to “solve the ‘deadhead’ fuel rail issue on the 1999-2003 Power Stroke engines.” It helps to eliminate air in the injectors. This will provide a quieter and smoother idle, and better throttle response, over stock. It also ensures a more consistent delivery of fuel to the injectors. This can help extend injector life.

15 Riffraff Diesel Performance offers two fuel upgrades for the 7.3L, in addition to the FRx. One is a High-Flow Banjo Bolt for the 7.3L. It can deliver significantly more fuel due to the larger area of the slotted hole. The other is their High-Flow Fuel CVD Fitting.

16 A new EBP (exhaust back pressure) sensor is a must on any 7.3L rebuild.

17 The turbo to pedestal interface must be resealed with new O-rings any time the turbo is removed.

18 The new Applied Performance turbo is almost the same size on the exterior as the OEM unit. However, the internals are built to move more air. The intake side has an 80-percent increase in volume capacity. More air equals more potential for power. It can also help lower EGT.

19 Here you see the Banks Power Elbow housing that was on our 7.3L Ford when the truck was acquired. This power part package is said to reduce “stock outlet and pipe backpressure by 40 percent.” Good parts like this were retained for reuse on this remanufactured 7.3L. It fits the new Applied Performance turbo as well as it did the stock one.

20A & 20B It’s common to find that the intake plenums on your 7.3L are crimped or otherwise damaged. The solution in the past has been to replace them. Now you can install a set of Riffraff’s RDP plenum reinforcement inserts. These can revitalize your damaged plenum intake openings and make them better than new.

21 With the engine partially assembled, it’s ready to be dropped into the truck. Final assembly and upgrades will be with it in place.

22 A quick tip to help eliminate squeak from the serpentine belt is to mask off the pulley and lightly bead blast the belt surface only.

23 The intake Spyder is installed with new boots from Riffraff.

24 The OE alternator was small and well used. A more powerful unit from DC Power was selected over a stock replacement. Seen here is their 190-amp HD series, and it’s said to provide a 15-percent amperage increase over stock, with 140 amps at idle. It has a 190-amp max average output.

25 Here you see a comparison between the 7.3L and 6.0L intercoolers. The larger unit is a stock 6.0L Power Stroke part. With very little work, this unit can be swapped into the older truck. Of course, this upgrade was done.

26 When upgrading a 7.3L to the 6.0L intercooler, the power steering cooler from the 6.0 must be used too. This is good, because it’s also larger. Domestic Diesel offers a fitting and line kit for this swap. Note: The 6.0L power steering cooler can be swapped into a 7.3L with the stock 7.3L intercooler as well.

27 The stock air cleaner housing was swapped out for a much better-flowing unit from S&B Filters. This also incorporates a new battery tray for the driver’s side.

28 With the better than new 7.3L under the hood, this truck is ready to roll.

Alliant Power

Applied Performance Products

ARP Automotive Racing Products

Banks Power

DC Power Engineering Inc.

Domestic Diesel

L&R Automotive Supply Co.

Riffraff Diesel Performance, Inc.

S&B Filters