i just bought a 13b engine and found out just today that the wiring harnes has been cut to bits, i need the car running but the end of next week and i dont have the money for a new harness so i was wondering if i could use the carburator and wiring harness from my 12a un till i get the money for the parts needed to make it fuel injected again.

 

Yes, but the manifold will not bolt up. Mazdatrix sells an adapter to connect 12A manifolds to 13Bs, or you can make one yourself.

Of course, the ignition system is different as well. You will need to move the dizzy and coils from the 1st gen over. And replace the 2nd gen high pressure EFI fuel pump with a lower pressure carb friendly pump. If you have cats, you'll likely clog them quickly.

It's a lot of work to go through for a downgrade.