--- a/modules/ajaxblocks/ajaxblocks.module
+++ b/modules/ajaxblocks/ajaxblocks.module
@@ -262,7 +262,7 @@
       $block_content = module_invoke($block->module, 'block_view', $block->delta);
       // Allow modules to modify the block before it is viewed, via either
       // hook_block_view_alter() or hook_block_view_MODULE_DELTA_alter().
-      drupal_alter(array('block_view', "block_view_{$block->module}_{$block->delta}"), $block_content, $block);
+      drupal_alter(array('block_view', "block_view_{$block->module}_" . str_replace('-', '_', $block->delta)), $block_content, $block);
       $content[$block_id] = array('content' => (isset($block_content['content']) ? render($block_content['content']) : ''));
       $settings_new = array();
       $js = drupal_add_js();