"Original" or not, the Truckstell is a key piece of the equation. As no GM overdrives were available for those years, the Truckstell would be the equivalent of a NAPCO upfit to GM. Except a whole lot more rarer than a Napco setup would be. I wouldn't consider a Napco upfit to be so unoriginal as to contemplate it's removal for the purpose of originality-not that anyone has suggested it-but I hope no one is thinking it either.
Truckstell made their OD's with the express intent of putting them into a specific model. Upon inspection I think you'll find number like A-104 on the OD. Congrats on your finds. And it's a nice quandary to be in. (as for the sale of the "other one", get the first one done and show it around at work and shows-you'll have plenty of buyers for it once people get to see what it's all about.:))
