727 in a 1966 dart wagon! HELP

Yes and yes; but again with the power level your working towards do you really want to worry about a small percentage difference, versus longevity?
But wait, what kindof back-end mods are you contemplating? Cuz if it don't hook well then does it really matter? But if you can make it stick, then it will matter very much.
You know when they blow up they can practically cut the car in half right? So you gotta run a blanket or something, and I doubt there's room in the tunnel for even the 904 and the blanket, So you might as well bite the bullet,open it up, and put the 727 in there. Then you can sleep at night.
Very true. I've got an 8 3/4 with a 3.55 and a locker sitting and to go in. I'm getting ready to do a spring relocation to get enough tire under there to at least try to hook up. The good thing about the s471 is it's super laggy, so it's not super hard on parts.