Hello, it seems gslse irons are easier to get than a 12a iron. First thing is it even compatable with the 12a. second are there any performance hits from the tiny ports, what is the portability of them, im only doing a street port for the center. Will it be able to handle a turbo ≈300hp without bottlenecking?
edit: will a 12a intake still fit when using the 12a front and rear irons

 

12a housings and gslse irons do mate. Coolant seals are in the rotor housing pre 86. The challenge I see is you would have a 6port 12a. None of the 6port intake manifolds (gslse , FC) would fit. Although I believe there were 6port 12a in Japan and Australia.

the odd part is I’ve seen 12a housings all fuggered up. With 12a irons being in way better shape.

 

i think he's asking if he can use the SE intermediate in place of a 12A intermediate.
if that's the case, then yes. just keep in mind that the SE ports and runners are smaller. i don't know if there is any space to try to get the SE runners (ported) closer to those of the 12A manifold though. i'm also not sure if the 12A manifold will cover the EGR port. those are the only minuses i can readily think of. on the plus side, you have gained injector ports.

that said, it should all bolt up just fine. there are no studs or bolts for the intermediate, so no issues there.

EDIT
as far as porting the SE intermediate goes, you should be fine for 300. in terms of what you should (or can) do, search using the member Jeff20B. i think i remember him posting photos of an SE intermediate he ported many years ago.

 

The GSL-SE *is* 12A parts. The end housings are from the 12A 6 port and the intermediate is from the 12A Turbo.

The ports are a lot smaller than a tallport 12A but they are the same size or slightly larger than a 12A intake manifold. My Racing Beat 4 port 13B Holley manifold matched perfectly, too.

About that... my other RX-7 has a bridge port 4 port 13B made with GSL-SE intermediate and rotor housings, and 12A end housings. It made over 200 at the wheels in 3rd gear naturally aspirated with a quiet exhaust. You'll be fine. I needed the GSL-SE intermediate for the motor mount and fuel injector provisions.

There is not that much metal around the port to open it up, either for port volume or for timing. I am not a fan of super late closing lines because I like a fat midrange, so this didnt bother me too much. Let me find the build thread...

https://www.rx7club.com/naturally-as...s-not-1003287/

Just for fun, a street port build I did.

https://www.rx7club.com/naturally-as...erent-1130673/