[snj8198]

that should be a 10 spline output shaft

im not sure if the th350 had the same adapter bolt pattern for the adapter as the manual trans but if so or not, you'll need the 8 bolt "race track" pattern adapter and change your coupler. The th350 is a 27 spline, you need a coupler with a 10 spline for the 465.

I like manuals and applaud your swap, however; i believe that if you are looking to make such a swap the NV4500 is well worth a look especially since I view the automatic to manual swap a fairly work intensive conversion.

Regardless, good luck with your project!