diff --git a/collects/tests/mzscheme/benchmarks/shootout/run.ss b/collects/tests/mzscheme/benchmarks/shootout/run.ss
index 2c802ec9d1..1e81b4ee46 100644
--- a/collects/tests/mzscheme/benchmarks/shootout/run.ss
+++ b/collects/tests/mzscheme/benchmarks/shootout/run.ss
@@ -36,6 +36,7 @@
       ("sieve.ss" "1200")
       ("spellcheck.ss")
       ("spectralnorm.ss" "5500")
+      ("spectralnorm-unsafe.ss" "5500")
       ("strcat.ss" "40000")
       ("sumcol.ss" #f ,(lambda () (mk-sumcol-input)))
       ("wc.ss")
diff --git a/collects/tests/mzscheme/benchmarks/shootout/spectralnorm-unsafe.ss b/collects/tests/mzscheme/benchmarks/shootout/spectralnorm-unsafe.ss
index 519c2a2d2a..77bebee048 100644
--- a/collects/tests/mzscheme/benchmarks/shootout/spectralnorm-unsafe.ss
+++ b/collects/tests/mzscheme/benchmarks/shootout/spectralnorm-unsafe.ss
@@ -9,8 +9,8 @@
          scheme/unsafe/ops)
 
 (define (Approximate n)
-  (let ([u (make-vector n 1.0)]
-        [v (make-vector n 0.0)])
+  (let ([u (make-flvector n 1.0)]
+        [v (make-flvector n 0.0)])
     ;; 20 steps of the power method
     (for ([i (in-range 10)])
       (MultiplyAtAv n u v)
@@ -21,9 +21,9 @@
     (let loop ([i 0][vBv 0.0][vv 0.0])
       (if (= i n)
           (sqrt (unsafe-fl/ vBv vv))
-          (let ([vi (unsafe-vector-ref v i)])
+          (let ([vi (unsafe-flvector-ref v i)])
             (loop (unsafe-fx+ 1 i)
-                  (unsafe-fl+ vBv (unsafe-fl* (unsafe-vector-ref u i) vi))
+                  (unsafe-fl+ vBv (unsafe-fl* (unsafe-flvector-ref u i) vi))
                   (unsafe-fl+ vv (unsafe-fl* vi vi))))))))
 
 ;; return element i,j of infinite matrix A
@@ -39,22 +39,22 @@
 ;; multiply vector v by matrix A
 (define (MultiplyAv n v Av)
   (for ([i (in-range n)])
-    (unsafe-vector-set! Av i 
+    (unsafe-flvector-set! Av i 
                         (for/fold ([r 0.0])
                             ([j (in-range n)])
-                          (unsafe-fl+ r (unsafe-fl* (A i j) (unsafe-vector-ref v j)))))))
+                          (unsafe-fl+ r (unsafe-fl* (A i j) (unsafe-flvector-ref v j)))))))
 
 ;; multiply vector v by matrix A transposed
 (define (MultiplyAtv n v Atv)
   (for ([i (in-range n)])
-    (unsafe-vector-set! Atv i
-                        (for/fold ([r 0.0])
-                            ([j (in-range n)])
-                          (unsafe-fl+ r (unsafe-fl* (A j i) (unsafe-vector-ref v j)))))))
+    (unsafe-flvector-set! Atv i
+                 (for/fold ([r 0.0])
+                     ([j (in-range n)])
+                   (unsafe-fl+ r (unsafe-fl* (A j i) (unsafe-flvector-ref v j)))))))
 
 ;; multiply vector v by matrix A and then by matrix A transposed 
 (define (MultiplyAtAv n v AtAv)
-  (let ([u (make-vector n 0.0)])
+  (let ([u (make-flvector n 0.0)])
     (MultiplyAv n v u)
     (MultiplyAtv n u AtAv)))
 
@@ -62,3 +62,4 @@
         (real->decimal-string
          (Approximate (command-line #:args (n) (string->number n)))
          9))
+