Having dual Carters on my truck, I'm a believer in rebuilding two carbs together to ensure they are setup exactly the same. However, if you can confirm they are jetted the same and the ventur's are identical, here is how I'd set them up. I would install the one with the auto choke in the rear. I would remove the butterfly from the manual choke so that it can never choke. Make sure you get a Uni-Syn tool to make the carbs play nice together.
