727 or 904?

The mid 70s 904 I had was for lack of better terms beefier than the 68 one I have.
Also If you can rebuild a carburetor you have twice the skill needed to rebuild a 904. Almost absolutely no special tools required at all. no special skills needed, just take it apart and put it back together with the new beefier parts. Remember I'm not sure if they'll be machine work needed but I think something about a removable sprag in the back to make it easier and serviceable or last longer I'm not sure. But like said people who really know will chime in soon. If 70aarcuda chimes in listen closely would be my advice.