It is my opinion that the T-5 is exactly what you need to get as much performance out of your 216. What is your tire height? 30.5 inch tires should help dial in that 216/T-5/4.56 gears.\combination. Don't be in a hurry to shift it into overdrive.
.72 overdrive creates quite a significant drop in RPM, leading to sluggishness if you shift into 5th gear too soon.
