diff --git a/alliance/src/pcbs/src/emulbs/Makefile.am b/alliance/src/pcbs/src/emulbs/Makefile.am
index 3f4409d8..860b8b89 100644
--- a/alliance/src/pcbs/src/emulbs/Makefile.am
+++ b/alliance/src/pcbs/src/emulbs/Makefile.am
@@ -1,7 +1,7 @@
 ## Process this file with automake to produce Makefile.in
 
 YACC = @YACC@ -d
-DEFS = @DEFS@ -DEMULBS_NBR_EMULBS=4 -DEMULBS_BS_SIZE=40 -DEMULBS_VERSION=\"@EMULBS_VERSION@\" -DPROGRAM_NAME=\"emulbs\"
+DEFS = @DEFS@ -DEMULBS_NBR_EMULBS=4 -DEMULBS_BS_SIZE=31 -DEMULBS_VERSION=\"@EMULBS_VERSION@\" -DPROGRAM_NAME=\"emulbs\"
 
 AM_CFLAGS = @ALLIANCE_CFLAGS@