{content block='some' page_tab='somename' block_group='somename' label='Test'
block_type='text' isleft='1'}

class.acBlockType_text.php add in function __construct:

$isleft     = isset($params['isleft']) && ac_utils::IsTrue($params['isleft']);

and

$this->SetProperty('isleft', $isleft );

and editconent.tpl line 224:

<div class="pageoverflow ac_content_block_id" style="{if
$content_block->GetProperty('isleft')}clear:none;float:left;padding-right:20px;{/if}">

Add this functionality if you can