Used to own a 81 RX-7 that despite having some problems was really nice and I regret getting rid of it. However, I did keep some of the spare parts around namely a 12a motor of questionable origins. Fast forward almost five years and I found a 1994 miata with a blown motor. I'm pretty sure you see where this is going. After removing the blown motor , the whole car was stripped because the top was ripped and the interior was wet, it smelled bad, and you don't need an interior to go fast. The plan was to mate a RX-7 bellhousing to the miata transmission but I'm still trying to work that out. With the help of my friend I was able to put the RX-7 bellhousing on but now it won't really shift through gears properly (or at all in some sometimes). I got drunk one night and bought the crappiest SA RX-7 in a storage auction for $70 and the plan was to use the transmission out of that car assuming it worked. So after the transmission comes out of the junk rx-7, it will be mated to the 12a, and I'll try to start it outside of the car. After that, hopefully make some motor mounts then finish assembling the cooling and fuel system. This project has taken a lot of time, partly from being busy with work and school, or from lack of funds and trying to do things on the cheap, or just from being burnt out on working on an oversized recycling bin for beer cans. I'll try to post more pictures as I take them or find them on my computer.

 

Cool. There is a lot of stuff you can do with a 12A.

 

I like the NB face on the NA!

 

Was the NB front end a straight forward install? Any tips or advice?

My next build will be a n/a rotary miata. I was planning to do the install in a nb but if i can get a na and install a nb front end id be happy with that too. Seems like all the rotary kits and such are more directed for na anyways.

 

I've been pondering this a lot too. If you're going to register it, the engine has to be newer than the chassis. So the only legal NA engine swap is an NA S5 13B into 90/91 miata chassis. That's probably why they kits are aimed at NA miatas.

 

^Must be a CA thing because none of that newer engine than chassis stuff matters in NY.

 

NB conversion is not easy from what I can tell. Didn't do the work myself but bought the car this way. From what I can tell the NB core support was used up front, and the NB fenders were cut and spliced onto the NA fenders so the lights and hood would line up. Not too worried about registering it because I live in central TX and there is no emissions testing just basic test for lights, brakes, etc..