I would agree with Belair.
Besides, I would build a 2.72 or 2.96 ratio instead of the OD. I have built a few 2.96s for 302 Z cars and it is a night and day difference in the way the car drives.
It makes a 3.31 rear drive like a 4.56 and a M21.
Besides overdriving a gearset puts more strain inside the trans case. Even though the Supercase is strong enough to take the stress, the cluster is always under load in an OD trans, because it has no "coast" position.
This is just my $.02 on the topic.
Eric