It’s been a couple of years since Virginia-based engine builder Sonny Leonard announced plans to offer the industry’s first 1,000-cubic-inch V8 for the auto racing and enthusiast market. His first bullet (shown above) displaced 1,005ci and pulled 2,118 horsepower at 7,700 rpm on the dyno. It was featured extensively in the media and is now racing in Australia.

But what has happened since with the 1,000ci program?

“There aren’t a lot of racing classes for engines with a 5.4-inch bore spacing,” Leonard tells EngineLabs. “Most of the rules say 5.3-inch.”

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Peter Thau assembled the Sonny Leonard mountain motor kit and is currently finalizing the tune for running on the street and drinking E85 fuel.

While Sonny’s Automotive Racing (SAR) is working overtime building mountain motors in the 900ci range based on 5.3-inch blocks, the shop has received only one other order for a 1,000ci engine — and that was in kit form. Leonard machined the block and heads, gathered up the proper cam, crank and induction system, along with the necessary hardware and accessories — and shipped the package to Peter Thau of CarTek in Denmark. And no full-time racing for this engine. Thau went “green” and built the ultimate E85 street/strip engine.

“It starts, idles and behaves like your new grocery car,” reports Thau, “but sounds like thunder!”

Thau says early dyno tests are showing over 1,360 horsepower and 1,314 lb-ft of torque, but he’s running out fuel at 5,500 rpm.

“I’m working on bigger injectors,” he adds.

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Here are a couple views from Cartek showing the assembly.

The street engine runs a 12.5:1 compression ratio while the race engine was built at 17:1. Other differences include a milder cam, and the billet 12.225-inch deck height block is machined with exterior scalloping to accommodate water jackets. Otherwise, short-block similarities include Bryant 5.875-inch-stroke crankshaft, GRP rods, SAR pistons (5.220-inch bore), ATI balancer, Jesel belt drive and Dailey dry-sump oiling.

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Note the size of the intake ports and runners...huge!

The SAR hemi-style heads are hogged out to the max and feature 2.900-inch Manley titanium intake valves and 2.100-inch exhaust valves. Jesel rockers and PSI springs round out the package.

The tall deck and wider bore spacing require a custom sheet-metal intake manifold, topped with four Accufab throttle bodies. The injectors are controlled with a BigStuff3 ECU while the spark is timed by MSD.

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The engin will be driven on the street as well as tested at the strip.

A ready-to-run 1,000ci engine from Sonny will run you about $115,000. Want to assemble it yourself, you can get about a $12,000 discount. With more emphasis on 5.3-bore-center engines, the cost will be lower and a wider variety of parts will be available. Leonard says the boat market is starting to show interest in mountain motors, especially turbocharged units. 

“But if anyone ever wants to go over a 1,000 cubic inches,” says Leonard, “we can do it!”

Meanwhile, EngineLabs will keep monitoring Thau’s progress as he finalizes the tune on his 1,000ci street engine. Be sure to check out the video above to hear the thunder.