I just got my second housing back from resurfacing and after putting it side by side with the other housing I planned on using it appears one of them has the spark plug hole spacing of an s5 but it does not have the knock sensor mount that the s5 housing does. does anyone have any idea what's going on? and more importantly does anyone have an s4 t2 housing with the larger gap between holes they would be willing to trade for one that has the smaller gap?

 

does it have a little N318 cast into it by the metering pump nozzle? if yes, than it is a JDM S4 housing.

 

I looked and on both housings there is no number cast by the nozzle but one has 13b cast above the word mazda and one doesn't.

 

if the spark plug spacing is different, you have 1 s4 t2 and 1 s5 t2.

Look up pictures of s4 t2 and s5 t2 housings. I identify s4 t2 housings by seeing a flat spot under the spark plug holes where a s5 t2 is rounded. Easiest way to tell in 2 seconds.