For many years Steve Morris has been working on a quad-turbo V16 engine for the Devel Sixteen supercar. The 748 ci (12,258 cc) V16 features a one-piece billet block, one-piece solid roller camshaft, crank (fires every 45 degrees), four heads, and four 81 mm turbochargers. Steve released a video two years ago when the engine hit the dyno limit at 4,500 hp. Steve recently put the monster engine back on the dyno showing it produce 5,007 horsepower and 3,757 lb-ft of torque at 7,000 rpm on 44 psi of boost.
Source: Steve Morris Engines