60s 727s vs 70s 727s

I'm betting you're talented enough to build one yourself. There's a couple good books on them. Carl Munroe, Tom Hand's books and the FSM of course. As Kimmer said, the '71 and up are believed to be more durable, with the wider front drum busing.

https://www.amazon.com/dp/B004XDM44K/?tag=fabo03-20