The coil connectors are different, but the hidden difference between the early 5.7 and the 6.1 is the crankshaft tone wheel. That is why the loop wire on the harness has to be either cut or intact, depending on which tone wheel is being used. The later 5.7's ( with same coil setup as 6.1 ) use the same tone wheel as the 6.1. That being said, I don't know what kind of tone wheel is used on the 6.4 or the 6.2 Hellcat engine.