From my data, both the JDM countershaft and the USDM countershaft (for the Del Sol VTEC) have 13 teeth for the first gear on the shaft.

The difference is in the first gear:

JDM 42 teeth, 42 / 13 = 3.23
Del Sol VTEC 43 teeth, 43 / 13 = 3.307

My question, does the 3.307 first gear of the Del Sol work with a B16 tranny / 4.785 final drive?

 

After enough research I've come to find my own answer: NO.

Here's why.

The JDM first gear that comes with the "kit" also comes with needle bearings.

These needle bearings carry dimensions 42x47x22 as opposed to the USDM needle bearings of 37x42x25.

So basically the JDM first gear / countershaft spline is larger, thus the reason you NEED the JDM first gear when swapping out the final drive. That's the ONLY gear that will work with that countershaft and that's the ONLY countershaft to work with the final drive gear.

 

Yes. You will need the matching B16 mainshaft and countershaft 1/2 gears and an aftermarket 4.785 FD with US fitment.