diff --git a/Tests/test_file_pcx.py b/Tests/test_file_pcx.py
index 6b15b2fb6..7621c1cc6 100644
--- a/Tests/test_file_pcx.py
+++ b/Tests/test_file_pcx.py
@@ -60,9 +60,9 @@ class TestFilePcx(PillowTestCase):
             px[x, 0] = x // 67 * 67
         self._roundtrip(im)
 
-    def _test_overflow(self, im):
+    def _test_buffer_overflow(self, im, size=1024):
         _last = ImageFile.MAXBLOCK
-        ImageFile.MAXBLOCK = 1024
+        ImageFile.MAXBLOCK = size
         try:
             self._roundtrip(im)
         finally:
@@ -74,7 +74,7 @@ class TestFilePcx(PillowTestCase):
         for y in range(4):
             for x in range(256):
                 px[x, y] = x % 128
-        self._test_overflow(im)
+        self._test_buffer_overflow(im)
 
     def test_break_one_in_loop(self):
         im = Image.new('L', (256, 5))
@@ -82,7 +82,7 @@ class TestFilePcx(PillowTestCase):
         for y in range(5):
             for x in range(256):
                 px[x, y] = x % 128
-        self._test_overflow(im)
+        self._test_buffer_overflow(im)
 
     def test_break_many_in_loop(self):
         im = Image.new('L', (256, 5))
@@ -92,7 +92,7 @@ class TestFilePcx(PillowTestCase):
                 px[x, y] = x % 128
         for x in range(8):
             px[x, 4] = 16
-        self._test_overflow(im)
+        self._test_buffer_overflow(im)
 
     def test_break_one_at_end(self):
         im = Image.new('L', (256, 5))
@@ -101,7 +101,7 @@ class TestFilePcx(PillowTestCase):
             for x in range(256):
                 px[x, y] = x % 128
         px[0, 3] = 128 + 64
-        self._test_overflow(im)
+        self._test_buffer_overflow(im)
 
     def test_break_many_at_end(self):
         im = Image.new('L', (256, 5))
@@ -112,7 +112,7 @@ class TestFilePcx(PillowTestCase):
         for x in range(4):
             px[x * 2, 3] = 128 + 64
             px[x + 256 - 4, 3] = 0
-        self._test_overflow(im)
+        self._test_buffer_overflow(im)
 
     def test_break_padding(self):
         im = Image.new('L', (257, 5))
@@ -122,7 +122,7 @@ class TestFilePcx(PillowTestCase):
                 px[x, y] = x % 128
         for x in range(5):
             px[x, 3] = 0
-        self._test_overflow(im)
+        self._test_buffer_overflow(im)
 
 
 if __name__ == '__main__':