Big-Block Chevy Engine Build - Project American Heroes: Shock & Awe

Project American Heroes Will Blow Away The Competition Thanks To Its 717-Horse Smeding Performance 572 Big-Block

Mike Harrington Oct 17, 2007 0 Comment(s)
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On a recent trip to the all-GM show in Carlisle, Pennsylvania, the opportunity to spend several hours touring the Gettysburg battlefield site presented itself. There is an almost a reverent atmosphere here, the place where tens of thousands of men perished over the course of three days. Right or wrong, North or South, they were still American soldiers fighting for what they thought was right.

Today our American solders are embroiled in conflicts around the globe. These solders are our fathers, mothers, brothers, sisters, sons and daughters. Our Project American Heroes '57 Chevy is a way to honor and support them. All parts, talents, and time have been donated. Once the vehicle is auctioned, all monies raised will be donated to the Armed Forces Foundation, earmarked for Iraq and Afghanistan war vets. (You can donate at any time at www.projectamericanheroes.org.)

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No hot rod project is complete with out a ground-pounding engine, and this is where Project American Heroes pulls out the big guns. Ben Smeding and the crew at Smeding Performance took the task of building the heavy artillery 572 big-block. Smeding Performance (Rancho Cordova, California) is best known for its dyno tested, turnkey crate engines. When Ben agreed to custom-build our 572, we couldn't have been more pleased and promptly jumped on a plane to Northern California.

After all was said and done, zero hour arrived and it was time to dyno test the monstrous 572. After its break-in period, every attempt to make a power pull resulted in a bogged down motor and an eventual blowback/reversion through the carburetor. Ben thought that a valve was not properly sealing. Sure enough, after checking the valves it was found to be a sticky hydraulic roller lifter. Note: This is why Smeding dyno tests and tunes every engine after it's built. After a lifter swap and final tuning, the 572 was ready. And it did not disappoint. At 5,900 rpm it produced 717.8 horsepower, and at 4,300 rpm engine torque peaked at 709.5 ft-lb. The throttle response on the 572 is excellent. At 2,500 rpm the torque is a frame twisting 565.9 ft-lb and only climbs higher as the accelerator opens up.

Shock and awe? No doubt about it.

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Starting with a standard Dart block with an unfinished bore, Smeding Perfomance crew member Daniel Moody bores each cylinder to a gaping 4.630-inch and applies the finish hone, then paints it black. The Rottler M65 boring bar will automatically bore each hole to exact tolerances. The machine also has the capability to parallel deck the block or recess the bottoms of the cylinder bore for connecting rod clearance on long stroke applications.

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Smeding bores the block to within .005-inch of the finished bore. The block is then final-honed with an automatic Rottler honing machine with a diamond hone. Smeding matches each piston to its respective bore. This was an easy process with the high-quality Ross pistons because each piston was almost dead-on in size when compared to the next.

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When it came to balancing, every part of the assembly is weighed separately (rods, pistons, wrist pins, rings, and bearings) to determine the bob weight.

When it came to balancing, every part of the assembly is weighed separately (rods, pistons, wrist pins, rings, and bearings) to determine the bob weight.

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