My son's first car...

My dad did the same for me (70 duster and all). 30 years later I'm so glad he did. Not sure if when you said "what do you guys think" you were inviting opinions...but if you can salvage the 904 I'd go that route. Lower gears through 1 & 2 and smaller/lighter. But maybe your 727 is already rebuilt and waiting. So pumped for you guys!