Overdrive solution?

Assuming you have a small block, a BB does not use any of these transmissions. The only thing I have been able to find is a Gear Vendors add-on unit. At $2600, its the cheapest out there. Another possibility is the Passion 4 speed OD manual, but it works out to be as expensive as the keisler setup. Overall, I am pretty disappointed with the availability of OD transmissions and adaptors. I don't mind cutting my floor, maunaul or auto, I just don't want to pay $5000.