i have the header for a 87 13b. would this fit on an 85 13b from a gsl-se?

 

I'll give you a clue. If you measure the header stud spacing distance between both rotors, I bet you'll get 13cm (gotta use a metric ruler or whatever as long as it's metric). A 12A measures 12cm. Thank Mazda for that one. Now armed with this knowledge, which year 13B do you think the header will fit?

 

so even repu 13b header's will work?