Hi i have a set of double bump heads but cant find any info on what they are, i cant find the casting numbers anywhere. numbers are 3748773L0. and instead of having the date info cast under that number it has (Canada) instead, also the small double bump on the end of the head has tapered sides and not straight up like info online. does anybody know or ever seen these before??? plz help!!!

 

 

I tried,fun looking up old stuff,one site,out of a 100,mre.books.com had some ok info