Big issues with BB mounts on Dart!

Can someone explain the notching? Big block mopars have external oil pumps, the K frames on small block and slant 6s will have to be notched or cut and rewelded to clear the pump.
Im doing the same build and hadnt heard of it also plan on using the 187. Thanks also will the torque strap fix it? torque strap has nothing to do with the notching needed, it only helps to limit or eliminate the rotational force of the engine to prevent ripping the motor mounts out on high horsepower motors. To pull maybe?
My answers in red