hello

I'm new here and have come in search of information pertaining to nailheads. We are building a hot rod, 36' 5 window ford coupe, and recently purchased a running nailhead with 55K on it to eventually put in the car. It is a '61 401 nailhead. Our question is what transmissions (automatic or manual) will bolt up with this? We obviously want something strong but dont want to purchase an adapter since they are so expensive. any ideas?

Thanks!