The X-Block 427 HO SC’s heart and soul is the new GM Performance X-block. This X-block engine family utilizes a Mast Motorsports engineered camshaft that is custom ground on a Mast Motorsports 3 bolt cam core. The 427 HO’s foundation is a fully machined X-block with a forged Callies rotating assembly with Mahle pistons that is topped off with Mast Motorsports CNC LS3 casting cylinder heads and a Whipple 2.9L Supercharger. ARP fasteners are used throughout and Mast Black Label pushrods ride on GM Cadillac High RPM hydraulic roller lifters. This hand built X-block based engine utilizes a camshaft that has a moderate lope that creates great RPM power across the band for the customer that will be aggressively racing their vehicle, but still wants great street manors for a daily driver.