I was reading your thread last summer but haven't been on here much this fall/winter. All caught up, looking real good! I'm going to tackle a 904 myself soon, it's going behind a 340 in '71 sweptline ratrod lowrider project I'm working on with my kid. I've watched those YouTube videos on the 727 rebuild, plus I have a couple books. Besides the sprag not bolting in, any other notable differences? I have a reverse manual valve body going in just to keep my shifting pattern the same as the Demon. Good luck with the rest of your mods!