I did some searching but couldn't find a definitive answer.

Will all Z-series Mazda engines and Duratec 4-pots bolt up to a Mazda Mx-5 gearbox? If so, what years of MX5 do I need to be looking at?

I know that the later MX5s use a box that will fit as they use a Duratec, it may be a 6speed box? As for fitting an earlier box I can't help

You'll want a gear box from a Mk3 MX5, late 2006 onwards. The 5 speed code is N7, but I don't know if the 6 speed has a different code. I'm pretty sure the Mk2 MX5s did not have MZR/Duratec engines.

The gear ratios for the 5 speed as far as I could find are:

1 - 3.71
2 - 2.19
3 - 1.54
4 - 1.18
5 - 1.00


The six speed is the same but with an extra gear. I don't know the ratio off hand.

Apparently the 6 speed is a fair bit bigger and the 5 speed is pretty tight in my Fury's transmission tunnel as it is. I've had to chop a few mounting brackets off the gear box to make it fit comfortably.

I have the same combo - N7 and Duratec will mate, however I understand that you will need a few of the Mazda mating parts. Don't know the definitive list but MKIndy7 on here is on his second install and has a thread detailing the install.

Another consideration is that the box causes the engine to lean over by 10deg, so you will need a modified sump.

I believe it's a great combination with a fantastic gear change action, however any bellhousing savings are cancelled by the above..