Flaagan,
Morgan Spares has a conversion kit that uses the Ford T-9 box. That's what's in my car. Reportedly, it's the conversion that requires the least amount of modification. There is a direct link to the install guide on their website, but it appears to be broken. I was able to find the link
here. I suggest you give Morgan Spares a call to discuss. I don't know the current situation with availability and pricing, but I'm sure they will let you know.
