As per your requirement you will need to create number of static blocks same as your drop-down values.
Now for example you have drop-down attribute values
Create your static blocks with identifier
static_blick_test1, static_blick_test2, static_blick_test3 etc...
Now in your phtml file you must have current product object and you can call it like.
<?php $attributeValue = strtolower($product->getAttributeText('custom_attribute_code')); ?>
Now based on this attribute value create your static block identifier like
<?php $staticBlockIdentifier = "static_block_".$attributeValue; ?>
Now you can call this static block like
<?php echo $this->getLayout()->createBlock("cms/block")->setBlockId($staticBlockIdentifier)->toHtml();?>
This way you can call your static block dynamically as per your custom attribute value in your product tab.