Here are some sites that give information about transmissions that I thought would be helpful.

http://www.tciauto.com/Products/TechInfo/trans_dims.asp

http://www.antiquechevytrucks.com/Content/Transmission%20Information/transmission_information.htm

http://www.drwtransmission.com/thm_200-4r.htm

An excerpt from the last article...

"Though the 200 gained a reputation as an undependable transmission early on in its life, most of this attributable to the early lock-up torque converter designs, the 200-4R is being used by and adapted to cars that demand a reliable overdrive, rear wheel drive transmission for high performance use. This transmission has surprised many transmission technicians that were used to seeing the many failing 200s. Many vehicles that are pumping out in excess of 700 horsepower are still using the 200-4R. The next step up for racing purposes being the mainstay THM 400."