Power brake Booster on 67 cuda/front disc

Hey 'all, I've got a 67 barracuda Formula S 273 commando w/power disc's in the front. My booster is bad and I can't find one anywhere :/ my parts store's warehouse can't get it and neither can Advanced, Summit doesn't appear to have one and I'm not sure where else to look :/ Will one off of a 74 dart work by chance? all I need is the booster, the MC is still fine