They fit perfectly, exept for the Academy ambulance because the mud guards are not bended enough at the front, but it can be easily repaired, like this :

here is the result with the Academy cab :

and with a PST Studebaker cab and a welded grill :

It worth it, even if it's really delicate. I can say it's better to glue them at the really end of your built !!...
You can have a look here :
http://www.limesmodel.hu/webshop-b/index.php?route=product/manufacturer&manufacturer_id=11&page=1
Pascal