Index: wp-includes/comment.php
===================================================================
--- wp-includes/comment.php	(revision 9315)
+++ wp-includes/comment.php	(working copy)
@@ -452,7 +452,7 @@
 			if ( defined('DOING_AJAX') )
 				die( __('You are posting comments too quickly.  Slow down.') );
 
-			wp_die( __('You are posting comments too quickly.  Slow down.') );
+			wp_die( __('You are posting comments too quickly.  Slow down.'), '', array('response' => 403) );
 		}
 	}
 }
Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 9315)
+++ wp-includes/functions.php	(working copy)
@@ -2206,10 +2208,14 @@
  *
  * @param string $message Error message.
  * @param string $title Error title.
+ * @param string|array $args Optional arguements to control behaviour.
  */
-function wp_die( $message, $title = '' ) {
+function wp_die( $message, $title = '', $args = array() ) {
 	global $wp_locale;
 
+	$defaults = array( 'response' => 500 );
+	$r = wp_parse_args($args, $defaults);
+
 	if ( function_exists( 'is_wp_error' ) && is_wp_error( $message ) ) {
 		if ( empty( $title ) ) {
 			$error_data = $message->get_error_data();
@@ -2243,7 +2249,7 @@
 
 	if ( !function_exists( 'did_action' ) || !did_action( 'admin_head' ) ) :
 	if( !headers_sent() ){
-		status_header( 500 );
+		status_header( $r['response'] );
 		nocache_headers();
 		header( 'Content-Type: text/html; charset=utf-8' );
 	}