I think that sometimes they will redo it as a 17* and that sometimes causes problems with a '94-'95.
Check out this link
It tells you how to put a 17* in a '94-'95. There are some mods required.
Here is a pic of a '94-'95 with the drainback valve.
Here is some more reading
7.3L DIT Anthology
Ford Motor Company Publication
This article outlines some of the various changes to the 7.3L Power Stroke engine since its introduction in the 1994 1/2 model year.
From Ford Motor Company Publication FSC 12922JA.
7.3L DIT Anthology
The crankcase was redesigned starting with engine serial number 375549 with thicker valley walls to increase stiffness to the assembly which reduces radiated engine combustion noise.
The crankcase was also modified in the tappet shelf area.
The valve train was redesigned to replace the cam follower guides and retainer to redesigned cam follower guide assemblies which bolt delivery into the crankcase to hold the follower in place.
The redesigned roller follower guide assemblies are now held in place with a capscrew for each pair of tappets which has led to the elimination of the roller follower guide retainer.
This change occurred at engine serial number 375549 .
Cylinder Head Gasket
Due to the change in the crankcase and valve train the cylinder head gasket was also changed.
The redesigned cylinder head gasket provides individual holes for each push rod which will guide the push rod ball seat into the lifter.
This redesigned cylinder head gasket can be used on previous engines.
A deareation valve was inserted in the front cover beginning with engine serial number 201681 through engine serial number 375549 .
The front cover was redesigned starting with engine serial number 375549 to help keep the oil pump primed for initial start up.
To accommodate this change, the pump inlet port was rotated 90° which moved the pickup tube from the left to the right.
The front oil cooler header gasket was also redesigned because of the change to the front cover.
The front cover has been modified for the updated reservoir to front cover gasket and passages have been cast and drilled into the front cover to incorporate the standpipe.
The engine serial number that the standpipe was incorporated is 201681 .
Oil Reservoir for the High Pressure Pump
As of engine serial number 187100 the reservoir has been cast and drilled to include the standpipe and is drilled, tapped, and spotfaced to use both a straight thread, o-ring sealed engine oil pressure sensor and inspection plug as sealing enhancements.
Due to the relocation of the pickup tube the oil pan baffle was redesigned to allow the pickup tube to pass through it to the bottom of the pan. This was done as of engine serial number 375549 .
California calibration, model year 1996-1997, utilized a " Split Shot " injector that in conjunction with the proper PCM calibration provides rate shaping capabilities. Our rate shaping provides an initial charge of fuel early in the injection cycle, followed by a larger quantity of fuel to complete the injection cycle. During the 1997 model year Econoline utilized the " Split Shot " injectors in all Federal and California calibrations.
Rate shaping of injection provides for a longer duration of the injection process, providing a cleaner, quieter burn.
Federal "F" Series (49 State and Canada) injectors were unchanged through the 1997 model year.
Note: Injector solenoids are now white in color instead of the prior black units. No functional change exists in the solenoids.
The fuel system has been improved by new fuel supply pipe assembly and banjo fitting. The new fitting on 1997 Econoline and 1997 California "F" series incorporates an accumulator to steady fuel pressure for the " Split Shot " injection system.
High Pressure Oil Pump The high pressure pump has had the drain check valve deleted. This brings the variation of high pressure pumps used on the DIT to three. The pumps may be identified by the absence or presence of the anti-drain check valve.
On 1994 1/2 and 1995 model year engines up to serial number 187099 , the initial high pressure pump did have a drain check valve but did not have an edge filter. The edge filter was part of the injection pressure regulator.
On 1995 model year engines starting with serial number 187100 , up to serial number 201680 , the high pressure pump did have a drain check valve and an integral edge filter. The edge filter was deleted from the injection pressure regulator.
On 1996 model year engines starting with serial number 201681 , the high pressure pump does not have a drain check valve but continues to have an integral edge filter.
High Pressure Pump Gasket
The high pressure pump gasket has been modified to seal the standpipe between the pump and front cover.
Note: The correct gasket must be used to prevent internal and external oil leaks.