64 Barracuda Engine Swap ?

THere is a thread here somewhere about the later head castings ( like 302 ) will break the earlier exhaust manifolds. The 2 castings hit at the lower rear corner.
Lower water pump port opposite side from your radiater. Mismatch between the later crank and your torque converters nose, etc..
All of the issues have been discovered and addressed in one manner or another. Lots of reading along with test fitting will get it together.