[Lynne]

First off, you need to define the variable $post to use it in the block.

But, besides that, variables are not html. You would need to create a PHP block to output a variable and there is an example there on how to do output in a php block:

$my_output = 'Hello, world.';
return $my_output;

An example using a variable:

$my_output = '<p>Hello '. vB::$vbulletin->userinfo[username].'</p>';
return $my_output;