I've got a turbo 400 with overdrive. :-) but the overdrive is a separate planetary transmission. It is called a Hono-drive, and is one of many brands that were built in late 60's and early 70's for the hot rodders and the off road market. Maybe you would be interested in persuing that option. I did a search on the net and found that there are still a lot of companies making this type of transmission. The advantage, is that it allows you to put an overdrive behind a very strong standard or automatic for less money spent. This is just one of the many I found.
http://www.gearvendors.com/ Bob
