Welcome aboard Don. This is a cool idea and you certainly sound like the right guy to tackle it if you felt like doing so. I don't have a book that would show whether 54-56 would be the same, but I do know there are differences between large series and small series, as well as power seat and non power. It is definitely a desired product as even good versions are split in some way. The biggest problem I see is that unless you get your product in a catalog or go the eBay route (my suggestion) is that they will be hard to sell. I have had some AC brackets made up for the early nailhead engines and I did it (much like you desire) for he good of the hobby and to recoop my costs. I have only sold a few, so just don't plan on quick return on your investment. Good luck.