6 HEMI Crate Engine Wiring Harness and Management by Modern Muscle Performance / ModernMuscleXtreme is proud to offer genuine MOPAR parts to our customers. This 6 / 392 HEMI crate engine wiring harness and engine management system is definitely one of those parts on our list. Hemi Standalone Harness – Swap Specialties Swap makes Gen3 Hemi standalone easy. Covering all Gen3 HEMI’s (5.7, 6.1, 6) our plug and play harness comes dyno tested and with a 3 wire hook-up your running! Weatherproof Fuse and relay box holds fan and fuel pump relays with outputs all ready for you to connect. We can also customize the harness to any fit whatever you need.