Transmission Choise

I have a vintage Chevy standard shift pickup with a 4.11 rear axle. I would like to use it to tow my car trailer. I would like to install a 700R4 transmission because of the low first gear and the overdrive feature. I will not be able to use any of the "E" models. I will also need a transmission with a mechanical speedometer drive. Question what year transmission should I look for? Is there a way to deal with the lock up converter?

I posted this question in engine talk but didn't get any answers. This is probably a better place to post. The truck is a street vehicle and gas milage is a factor. Thanks.