Purchased a speedometer cable and ratio adapter from

ACI Engineering
6728 Lovers Lane
Portage, MI 49002
616-327-1991

Sent my original cable to ACI Engineering. They built be a new cable which allowed me to connect my original speedometer to a right angle ratio adapter and then to the transmission (GM Borg Warner T5).
Below is the cost break down of the system and a picture.

How I got started was I talked to Tom at ACT Engineering. He had me send my old MG speedometer cable to him so he could get the speedometer connection correct. The length of my original cable was perfect (about 4') so that is what he made the new cable length to. Received the new cable from ACI in about a week and installed it on the car. Went out on the highway and used the mile markers on the side of the road to check the odometer. Worked out that for every mile I traveled the odometer said I traveled about 1.35 miles. Gave this information to Tom at ACI and he worked up a right angle ratio adapter that slowed down the speedometer. I needed a right angle adapter due to the amount of space in the transmission tunnel. Received the right angle adapter in about a week. While I was taking the odometer readings I was also making speedometer observations using a GPS receiver. When the speedometer read 100 MPH the GPS receiver said I was doing 70MPH. Talked to Tom about this and he said he works off the more accurate gear driven odometer to get the ratio adapter right. After installing the ratio adapter on the car the odometer and speedometer are accurate.