Byron's 6.4L HEMI Dodge Challenger Engine Swap Hits the Dyno! Here at MMX, we were able to add 176 Wheel Horsepower over the stock 5.7 VVT engine on Byron’s personal 2021 Challenger! If you are looking for serious naturally aspirated power, and a head turning idle sound, give us a call today! This also answers a question we have been receiving recently, our new HI-RAM camshaft does still work very well and makes great power with the OEM 6.4L intake manifold! This is one of THE most powerful cams