diff --git a/tornado/simple_httpclient.py b/tornado/simple_httpclient.py
index 79a5960c..5bf3d158 100644
--- a/tornado/simple_httpclient.py
+++ b/tornado/simple_httpclient.py
@@ -361,6 +361,11 @@ class _HTTPConnection(object):
             if self.code == 303:
                 new_request.method = "GET"
                 new_request.body = None
+                for h in ["Content-Length", "Content-Type"]:
+                    try:
+                        del self.request.headers[h]
+                    except KeyError:
+                        pass
             new_request.original_request = original_request
             final_callback = self.final_callback
             self.final_callback = None