Big Block 72 Dart

TransDapt.
Mounts for B/RB engine to your '72 slant 6 K frame:
Engine Performance & Vehicle Customizing Products From Hedman | Hedman Performance Group
Mounts for B/RB to V8 (LA) K frame (biscuit type, '67-'72, you didn't specify what you got):
Engine Performance & Vehicle Customizing Products From Hedman | Hedman Performance Group
Done.