diff --git a/src/r63w72.f b/src/r63w72.f
index 05895c8f..8c369982 100644
--- a/src/r63w72.f
+++ b/src/r63w72.f
@@ -1,10 +1,10 @@
 C> @file
-C> @brief Convert w3fi63 parms to w3fi72 parms.
+C> @brief Convert w3fi63() parms to w3fi72() parms.
 C> @author Mark Iredell @date 1992-10-31
 
-C> determines the integer pds and gds parameters
-C> for the grib1 packing routine w3fi72 given the parameters
-C> returned from the grib1 unpacking routine w3fi63.
+C> Determines the integer PDS and GDS parameters
+C> for the GRIB1 packing routine w3fi72() given the parameters
+C> returned from the GRIB1 unpacking routine w3fi63().
 C>
 C> Program history log:
 C> - Mark Iredell 1991-10-31
@@ -14,20 +14,18 @@
 C> - Chris Caruso 1998-06-01 Y2K fix for year of century
 C> - Diane Stoken 2005-05-06 Recognize level 236
 C>
-C> Usage:    call r63w72(kpds,kgds,ipds,igds)
-C>
-C> @param[in] kpds integer (200) pds parameters from w3fi63
-C> @param[in] kgds integer (200) gds parameters from w3fi63
-C> @param[out] ipds integer (200) pds parameters for w3fi72
-C> @param[out] igds integer (200) gds parameters for w3fi72
-C>
 C> @note kgds and igds extend beyond their dimensions here
 C> if pl parameters are present.
 C>
+C> @param[in] kpds integer (200) PDS parameters from w3fi63().
+C> @param[in] kgds integer (200) GDS parameters from w3fi63().
+C> @param[out] ipds integer (200) PDS parameters for w3fi72().
+C> @param[out] igds integer (200) GDS parameters for w3fi72().
+C>
 C> @author Mark Iredell @date 1992-10-31
       SUBROUTINE R63W72(KPDS,KGDS,IPDS,IGDS)
       DIMENSION KPDS(200),KGDS(200),IPDS(200),IGDS(200)
-C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
 C  DETERMINE PRODUCT DEFINITION SECTION (PDS) PARAMETERS
       IF(KPDS(23).NE.2) THEN
         IPDS(1)=28                      ! LENGTH OF PDS
@@ -70,7 +68,7 @@ SUBROUTINE R63W72(KPDS,KGDS,IPDS,IGDS)
         IPDS(26)=0                      ! PDS BYTE 29
         IPDS(27)=0                      ! PDS BYTE 30
       ENDIF
-C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
 C  DETERMINE GRID DEFINITION SECTION (GDS) PARAMETERS
       IGDS(1)=KGDS(19)                  ! NUMBER OF VERTICAL COORDINATES
       IGDS(2)=KGDS(20)                  ! VERTICAL COORDINATES
@@ -113,6 +111,6 @@ SUBROUTINE R63W72(KPDS,KGDS,IPDS,IGDS)
           IGDS(18+J)=KGDS(21+J)
         ENDDO
       ENDIF
-C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
       RETURN
       END
diff --git a/src/w3fi74.f b/src/w3fi74.f
index cc3f3a83..c68c29a7 100644
--- a/src/w3fi74.f
+++ b/src/w3fi74.f
@@ -1,33 +1,18 @@
 C> @file
-C> @brief CONSTRUCT GRID DEFINITION SECTION (GDS)
+C> @brief Construct Grid Definition Section (GDS).
 C> @author M. Farley @date 1992-07-07
 
-C> This subroutine constructs a grib grid definition section.
+C> This subroutine constructs a GRIB grid definition section.
 C>
-C> Program history log:
-C> - M. Farley 1992-07-07
-C> - Ralph Jones 1992-10-16 Add code to lat/lon section to do
-C>                         gaussian grids.
-C> - Ralph Jones 1993-03-29 Add save statement
-C> - Ralph Jones 1993-08-24 Changes for grib grids 37-44
-C> - Ralph Jones 1993-09-29 Changes for gaussian grid for document
-C> change in w3fi71().
-C> - Ralph Jones 1994-02-15 Changes for eta model grids 90-93
-C> - Ralph Jones 1995-04-20 Change 200 and 201 to 201 and 202
-C> - Mark Iredell 1995-10-31 Removed saves and prints
-C> - M. Baldwin 1998-08-20 Add type 203
-C> - Boi Vuong 2007-03-20 Add type 204
-C> - George Gayno 2010-01-21 Add grid 205 - rotated lat/lon a,b,c,d staggers
+C> @note Subprogram can be called from a multiprocessing environment.
 C>
-C> @param[in] IGDS Integer array supplied by w3fi71()
+C> @param[in] IGDS Integer array supplied by w3fi71().
 C> @param[in] ICOMP Table 7- resolution & component flag (bit 5)
-C> for gds(17) wind components
-C> @param[out] GDS Completed grib grid definition section
-C> @param[out] LENGDS Length of gds
-C> @param[out] NPTS Number of points in grid
-C> @param[out] IGERR 1, grid representation type not valid
-C>
-C> @note Subprogram can be called from a multiprocessing environment.
+C> for gds(17) wind components.
+C> @param[out] GDS Completed grib grid definition section.
+C> @param[out] LENGDS Length of gds.
+C> @param[out] NPTS Number of points in grid.
+C> @param[out] IGERR 1, grid representation type not valid.
 C>
 C> @author M. Farley @date 1992-07-07
       SUBROUTINE W3FI74 (IGDS,ICOMP,GDS,LENGDS,NPTS,IGERR)
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index e9067d7d..762a7e83 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -7,7 +7,7 @@ if(BUILD_D)
 
   # This function builds and runs a test.
   function(w3emc_test name)
-    add_executable(${name} ${name}.f90)
+    add_executable(${name} ${name}.F90)
     target_link_libraries(${name} PRIVATE w3emc_d)
     add_test(NAME ${name} COMMAND ${name})
   endfunction()
@@ -16,4 +16,5 @@ if(BUILD_D)
   w3emc_test(test_summary)
   w3emc_test(test_w3tagb)
   w3emc_test(test_w3fi71)
+  w3emc_test(test_w3fi74)
 endif()
diff --git a/tests/test_summary.f90 b/tests/test_summary.F90
similarity index 100%
rename from tests/test_summary.f90
rename to tests/test_summary.F90
diff --git a/tests/test_w3fi71.f90 b/tests/test_w3fi71.F90
similarity index 100%
rename from tests/test_w3fi71.f90
rename to tests/test_w3fi71.F90
diff --git a/tests/test_w3fi74.F90 b/tests/test_w3fi74.F90
new file mode 100644
index 00000000..37ac14b9
--- /dev/null
+++ b/tests/test_w3fi74.F90
@@ -0,0 +1,44 @@
+! This is a test in the NCEPLIBS-w3emc project.
+!
+! Test the w3fi74() function.
+!
+! Ed Hartnett, 2/28/23
+program test_w3fi74
+  implicit none
+  integer igrid
+  integer igds(200)
+  integer icomp
+  integer npts
+  character*1 gds(200)
+  integer lengds
+  integer ierr
+  integer i
+  character expected_gds(32)
+  expected_gds(:) = (/ char(0), char(0), char(32), char(0), &
+       char(255), char(5), char(2), char(178), char(2), &
+       char(198), char(128), char(144), char(35), char(131), &
+       char(92), char(34), char(0), char(129), char(56), &
+       char(128), char(0), char(49), char(156), char(0), &
+       char(49), char(156), char(128), char(64), char(0), &
+       char(0), char(0), char(0) /)
+
+  print *, "Testing w3fi74..."
+
+  ! Fill the igds array. This call comes from test_w3fi71.F90.
+  igrid = 172
+  call w3fi71(igrid, igds, ierr)
+  if (ierr .ne. 0) stop 1
+
+  ! Fill the igds array. This call comes from w3if72.f.
+  icomp = 0
+  npts = 4
+  call w3fi74(igds, icomp, gds, lengds, npts, ierr)
+  if (ierr .ne. 0) stop 1
+  if (lengds .ne. 32 .or. npts .ne. 489900) stop 2
+  do i = 1, 32
+     if (gds(i) .ne. expected_gds(i)) stop 4
+     !print *,'char(', ichar(gds(i)), '), '
+  end do
+
+  print *, "SUCCESS"
+end program test_w3fi74
diff --git a/tests/test_w3tagb.f90 b/tests/test_w3tagb.F90
similarity index 100%
rename from tests/test_w3tagb.f90
rename to tests/test_w3tagb.F90