I have not came across this before. I suppose best thing to do would be to fabricate an inlet manifold to suit the mx5 head, and your selected carbs, junk the ecu, and take the car to a rolling road to get the carbs set up correctly. It could take some time trying to identify the correct jet sizes. I think that you need to prioritise which is of more importance, mx5 engine or webbers. If you want webbers, go for a pinto. In my opinion, it will cost a lot of money and time, not only to get it all fabricated up nicely, but to get it running correctly. You may have an issue if you junk the ecu on a 1.8 as I believe the engine runs variable valve timing. Best thing would be to ring a company called race shak, based in Tewksbury Gloucestershire. These boys are amazing at stuff like this, and are also main dealers for omex. But it will cost you a load of wedge I am sure ! Happy hunting.
