Thanks guys,

From what I've learned so far, there were definitely a few diferent foundries given contracts to cast the housings. Mazda probably pressed and machined the inside chrome sleeves at their Plant in Hiroshima(for j-spec & a-spec).

So, really the only difference is in how the exterior castings look,

The housing casts Mazda made have the factory stamp and are slightly better looking in my opinion. Oh btw, the repair shop does have, and is giving me an identical set to the ones in the picture.

Just had another thought...If there were a few other plants making the housing casts, then the ones Mazda made in-house should also be more rare. #https://www.nopistons.com/forums/pub...#>/biggrin.png

Thanks again guys, and if anyone knows any thing more/different please share, as much of what I have is hearsay.



Newguy707

what IS the diffrence between 13B RE and 13B REW???

port shape.



alot of the differences are external.

it is JDM!!!!!!!!!!!!!!!!!!!!!!!!!



nah, just port sizes, and different manifolds,etc.