1005.8ci Godfather Big Block Engine - The Biggest Rat Ever!

Check out the “Godfather” versus a standard GM big-block; the crank centerline stands at 12.225 inches from the deck while the big-block checks in at 9.80. It’s also about 8 inches wider at the top of the valve covers and the cam bore is raised nearly 2 inches to make room for the crank’s massive throw. Options include water jackets, stock big-block water pump mounts, and side engine-mount lugs. Shown here is the full-race block with no water jacket.

Lift numbers like that require a stronger cam core. Here’s a closer look at the drastic difference in base circle versus a standard big-block cam (left). The practically rectangular lobes are ground on a 121-degree lobe-separation angle with a 118-degree centerline. The intake is advanced 3 degrees.

You can’t use standard GM paired guide bar roller lifters with their wee little 0.842-inch body to transmit 1-inch-plus lift, so Leonard relies upon burly keyed Cam Effects or Jesel roller lifters with 0.950-inch wheels in a 1.095-inch body that could practically double as small casters.

Coming in just a bit under 6 inches, the 5.875-inch stroke of the Godfather’s billet steel crank (left) is comically larger than a common 4.25-inch-stroke 454 unit (right).

The valves will never see all that lift if the pushrods buckle under pressure, so rather than ⅜-inch pushrods, the Godfather uses ⅝-inch pushrods—11.300 inch on the intake, and 12.735 inch on the exhaust.

Every part of the Godfather’s crank (right) grew except the bearing surfaces; it still uses big-block Chevy main and rod bearings.

Most 540ci big-block strokers use a 6.385-inch rod (bottom). To create 1,005 cubes, the Godfather requires rods in the 8-inch range. The GRP aluminum rod shown here is only for full-race versions; the aforementioned street versions will get billet steel rods.

Pondering how much work it would take to get one in a muscle car? If you’re up to the challenge, Leonard’s got you covered. Godfather number two was actually built as a slightly less radical pump-gas version intended to go in a street car down in Australia. That one “only” makes 1,650 hp at 7,000 rpm, and 1,400 lb-ft at 5,700. Why? “For the bragging rights,” was the response.

Redefining the concept of “big bore,” the Godfather’s piston measures 5.220 inches in diameter. For comparison, the bore on a standard 454 big-blocks measures 4.251 inches.

The fabricated sheetmetal intake mounts four 2.750-inch (id) two-barrel Accufab throttle-bodies that flow 924 cfm each for a total of 7,392 cfm from all eight. Eight 65-lb/hr main injectors and eight 35-lb/hr supplemental injectors are used to fuel the Godfather. The supplemental injectors only come on under WOT.