Torqueflite Speedometer gear choice

Were currently rebuilding the 727 for our 63 valiant build. And I started searching for the correct gear for our setup.

3.73 gear. 245/60/15 tire (26.57).

Falls around 37 tooth on the charts I've found.

Where's a good place to purchase?

We currently have a 30 tooth.

Thanks. Eric and Jason