We build a twin-turbo-capable 420-inch Gen III Hemi for install in a Hellcat-pounding SRT8 Challenger. We’re tackling clearance issues and all the challenges that come with putting aftermarket parts in a stock block. From crankshaft installations to piston prep, we're all about making that 426 cubic inch beast roar to life. We even take a break to splash some flashy red paint, making it just as fierce on the outside as it is on the inside.