It's just my personal bias, but I'm not a fan of total frame swaps like that. I think that you'll find that it's gonna be a whole lot of work to make it fit, and then when you look at it from the bottom it'll be a bit of a mess adapting body mounts, etc to make it all fit. I'd stick with the '40 chassis unless it's a rusty mess, but that's just me. Others seem to like the idea of a later model chassis under old iron.