3.636 speedo drive
 

You guys probably already know that mazda never released a 3.636 final drive in any of the NA miatas.
What people fail to realize is that the NA speedometer is driven off the tailshaft of the transmission via a mechanical drive and cable. Because mazda never offered this final drive ratio, they never offered a corresponding mechanical drive for miata application.

After going through all the (wrong) "internet wisdom" on this topic, and after 3 attempts, I've finally built a 3.636 speedo drive. Who knew that old 929 parts could be useful again?

Oh, and if you were wondering what that tall of a gear does with a 5 speed, 60 mph indicates 2500 rpm. :)

So for you patient people still waiting for their 3.636 gearsets with NA speedo drives, have hope. I've received all of the main parts, but I needed to order some oil seals and capture pins. You're going to have to put together your speedo drives, which is not too hard: a body, a gear, a pin, oil seal, and an o-ring. You'll see what I mean when you get your stuff. I'm expecting to have these shipped out Thursday.