440 in 73 Dart Sport, Convert to Manual Brakes?

I agree with the suggestion of Mancini Racing. They seem to be the universal go-to butt savers for Mopar guys.

As for switching to manual brakes...I get why the space will be critical with the big block swap...but nothing like adding ~200lbs to the front of the car and suddenly needing 3x the pedal effort. :D

You'll be fine...I've personally never even driven a classic Mopar that didn't have manual brakes and they all stopped as well as I had expected...but I still suggest practicing some emergency stops and threshold braking before you do any horsing around with that hot new motor.