Big is a relative term, since it always requires some level of qualification or comparison to justify. For example, 496 ci sounds like a lot of engine, until it’s sitting next to a 572, which itself is smallish next to a 632ci, 10.2-inch deck Merlin-based big-block Chevy. And even that’s laughably miniscule when stacked against the offerings in the world of Pro Stock drag racing that soar up into the 700 to 900ci range. And we’re still talking about comparatively puny traditional pushrod-style automotive V-8s here. Plenty of military and industrial engines push more air in one cylinder than all of those engines combined.

But in our world of hot rodding and racing, the limit for traditional-style blocks has always been in the three-digit range. That’s because the thing about creating more cubic inches is that you can only bore and stroke just so far before you bump up against the physical limitations of the block. Going for more means the block itself has to grow on every axis to accommodate bigger slugs, and in the cylinders more throw from the crank, and reach from the rods. Basically you have to design a bigger big-block. The only question is just how big do you want to go? Historically, the glass ceiling has always been the magical fourth digit. There just hasn’t been a traditional-style block that could package parts large enough that wouldn’t burst through. Until now, that is.

Sonny Leonard Racing Engines has always specialized in “big.” Their smallest offering comes in at around 611 ci and reached all the way up to 940 ci. Never satisfied and always looking to innovate and improve, Leonard decided it was time to create the biggest big-block on the planet: a 1,005.8ci behemoth with an unreal 5.220-inch bore and a 5.875-inch stroke. Leonard calls it the “Godfather,” and it’s hard to fault that bit of bravado since he can back it up with numbers like 2,150 hp at 8,000 rpm and 1,500 lb-ft of torque at 6,200 rpm on 112-octane fuel. That’s naturally aspirated, by the way.

Previously, Leonard had always theorized that a 1,000-plus cube drag race engine just wasn’t feasible considering the criteria required to make it live and produce power that justified the all clean sheet design it would take. Prodding from CEO Racing’s Craig Olson is what finally pushed Leonard to accept the challenge. Olson, a loyal customer, wanted something bigger and badder than the Leonard-built 935ci engine he used to set the record in Top Sportsman with a 6.25 pass at 223 mph.

Please understand, calling the Godfather a “big-block” is little more than an aesthetic classification, since it shares absolutely nothing with traditional GM and aftermarket-based big-block Chevys, other than the main and rod journal sizes and bellhousing bolt pattern. Nevertheless, we just couldn’t resist the chance to take a peek at some of the specialized outsized components that make this engine possible. We feature a lot of really big, really powerful engines in PHR, but this bad boy takes the cake.

Will it Fit?

Surprisingly, it might. The Godfather is 34 inches wide at the valve covers’ outer edges, and from crank centerline to the top of the throttle body it’s 26.5 inches. Lengthwise, it is 32 inches from the flywheel flange to the crank bolt—that’s only 1.4 inches more than a stock big-block Chevy!

“Big is a relative term … 496 ci sounds like a lot of engine, until it’s sitting next to a 572…”

“Leonard decided it was time to create the biggest big-block on the planet: a 1,005.8ci behemoth…”

“…in our world of hot rodding and racing, the limit for traditional-style blocks has always been in the three-digit range.”

“Sonny calls it the ‘Godfather,’ and it’s hard to fault that bit of bravado since he can back it up with numbers like 2,150 hp at 8,000 rpm…”