PG 7.1 doesn't have the old block size restrictions
You might still want to edit your /etc/rc.d/init.d/postgresql file
so the line that starts it up uses a lot more RAM:
su -l postgres -c "LC_ALL=C /usr/bin/pg_ctl -D $PGDATA -p
/usr/bin/postmaster -o '-B 2000 -o -S2000' start >/dev/null 2>&1"
< /dev/null
(Above should be a single line in your file).
But there is no block size limit any more.