They took Mopar's fine 375-bhp 440-cid Magnum V-8 and treated it to the time-honored hop-up of more carburetion, replacing the single Carter quad with three Holley two-barrels on an Edelbrock Hi-Riser manifold. Normal driving ran the engine on the center carb; punching it opened the two outboard Holleys and delivered an astounding 1375-cfm charge. Hemi valve springs, a hotter cam, magnafluxed connecting rods, and other fortifications helped boost output to 390 bhp.