Custom Content types nodes with Nodeblocks module
Figured it out by getting my head around what Drupal calls "Template Suggestions".  The Theme Developer Module helped.

For my particular use case I had to create a template file called block--nodeblock.tpl.php to override the default block output. I basically stripped everything out of the default except the actual content so that this was all that was left: &lt;?php print $content ?&gt;. 

Then I made a node--content_block.tpl.php template to override this particular content type's display the way I wanted it.  I had to add some trim() methods to strip out some leading spaces that Drupal insisted on inserting. 

&lt;div id="node-&lt;?php print $node-&gt;nid; ?&gt;" class="&lt;?php print $classes; ?&gt; clearfix"&lt;?php print $attributes; ?&gt;&gt;

    &lt;?php if($content['field_headline']): ?&gt;
        &lt;?php print render($title_prefix); ?&gt;
        &lt;&lt;?php print trim(render($content['field_headline_level'])) . ' ' . $title_attributes; ?&gt;&gt;&lt;?php print trim(render($content['field_headline'])); ?&gt;&lt;/&lt;?php print trim(render($content['field_headline_level']));?&gt;&gt;
        &lt;?php print render($title_suffix); ?&gt;
    &lt;?php endif ?&gt;

    &lt;div class="content"&lt;?php print $content_attributes; ?&gt;&gt;
        &lt;?php print trim(render($content['field_content'])); ?&gt;
    &lt;/div&gt;

&lt;/div&gt;


The last thing I had to do was create a template to strip out all the extra tags that the Drupal default field comes with.  I did so with this file, named field--content_block.tpl.php:

&lt;?php foreach ($items as $delta =&gt; $item) : ?&gt;
      &lt;?php print render($item); ?&gt;
&lt;?php endforeach; ?&gt;