what exactly is the diffrence bewteen a 12a and 13b header?

 

Centerline Distance between the Exhaust Flanges

 

Are you trying to see if a header from a 12a will fit on your 13b? If your looking for swap info on 13b's. All 84-92 13b 6port headers will interchange. It's the rest of the system that needs alittle massaging. rx7doctor

 

it's in this link right here: https://www.rx7club.com/search.php

 

If you can find a used "ROTARY ENGINEERING" header, grab it immediately. Unlike Racing Beat, there is no one-piece header to engine flange. So by cutting the rear flange (where the 2 headers connect), you can use it also on a 13-B motor.

 

good stuff guys.
so heres my situation. my dad has an old 12a with custom headers, im just wondering if there would be too much work to put the heards of the 12a onto my 13b

 

you can make a 12a header fit a 13b no problem