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Cheap Big-Block Chevy Engine Build - $2,650 Big-Block Chevy

Don't Spend A Fortune, Build A . . .

By Richard Holdener, Photography by Richard Holdener

We're famous for our low-buck engine builds. Longtime readers have been treated to high-winding small-blocks with stock rod bolts and sketchy, solid-cammed, big-bore stump pullers that we're not afraid to rev way past the recommended redline. Our secrets are to scrounge a short-block from a wrecking yard, fix only what is necessary, assemble the engine ourselves, and wear the proper protective head and eye gear when standing near the running engine.

This engine is different. Demon Engines in Sante Fe Springs, California, sells low-buck 454s as service replacements, advertising an honest 400 hp and more than 500 lb-ft for just $2,650 outright. What intrigued us about the Demon engine was that it came nearly complete, from intake to oil pan, minus only the carburetor. It features a four-bolt block and is available in either Mark IV or Gen V guise with no changes in power output. Obviously, for less than three large, we didn't expect to find many racing components. What we did find was a motor perfectly suited to the combination of power level and engine speed. The four-bolt block was precision-machined then fitted with new rings and bearings along with a factory cast-steel crank, reconditioned factory rods (including a rod bolt upgrade), and 9.4:1 forged pistons from Probe Racing. According to Demon Engines, the short-block can stomach power levels above 700 hp and 7,000 rpm and heavy doses of nitrous. We may well take up Demon on its offer to abuse this engine in the future, but for now, we were interested in seeing what this baby had to offer in as-delivered trim.

Producing 400 hp is not terribly difficult in a motor displacing 454 ci. Truth be told, the motor actually displaces 461 ci thanks to a 0.030 overbore, but even 400 hp requires something more than a stock cam profile. Keeping costs down meant skipping the more expensive roller cam and sticking with a hydraulic, flat-tappet version. The mandatory loss of zinc content in current motor oils had many enthusiasts abandoning flat-tappet cams, but according to Demon Engines, there is no need for concern with proper preparation. In fact, Demon was quick to point out that it has never lost a flat-tappet cam or lifter on any of its engines. The company's procedure for a long life includes moly-based assembly lube on the cam and lifters prior to installation, prelubing the motor prior to start-up, and use of a high-quality Lucas oil and high-zinc break-in lubricant. Perhaps a touch of overkill, the procedure has proven successful, so we followed it to the letter prior to starting our 454. The cam supplied in our 400hp combination was a mild Comp Xtreme Energy XE268H that offered a 0.515/0.520-lift split, a 224/230 duration at 0.050, and a 110-degree lobe-separation angle. Small by big-block standards, the grind offered an impressive combination of idle quality and torque production.

By Richard Holdener
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