Power brakes??

No it is not. I was going to fab something up to get the needed clearance, might be part of my 68 Dart refresh in the works. Was looking at the Van setup how it puts the MC sideways. Was not going to use as is but I think I might be able to get an inch more clearance by moving to the left some.

Gotcha!
I checked my FSM; In 1969, the bellcrank could be had on three different units;
The one I'm thinking of is called a Midland-Ross Tandem Diaphragm.No other info in the brake section.