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.
All the Demon 454 combinations start out as BBC core motors. To ensure quality, Demon handpicks cores for its low-buck applications. The 454s are available in Mark IV and Gen V configurations with no difference in power production.
The choice of peanut-port cylinder heads from a mid-to-late-'80s TBI big-block may concern a few enthusiasts, but the power numbers certainly demonstrated their potential. In fact, Demon was quick to point out that with a minimal amount of work, the peanut-port heads will support more than 500 hp, so they are more than adequate for 400 hp. What the small ports bring to the table is improved part-throttle response and torque production. Sure, huge rectangular ports will make more power, but they will not match the driveability of the small peanut ports. For every job there is a tool, and the peanut-port heads work very well on this application. As supplied for the 400hp 454, the heads maintain the factory valve sizing but receive a fresh surfacing, a competition valve job, and a new spring package to work with the Xtreme Energy cam profile. The heads are secured using Fel-Pro head and intake gaskets. Working with the heads and cam is a dual-plane intake from ProComp. The Air-Gap-style intake offers impressive performance throughout the rev range, despite that it was originally intend-ed for the larger oval-port heads. According to Demon, the port mismatch is inconsequential at this power level, and testing with dedicated peanut-port intakes demonstrated a drop in power compared with the ProComp unit.
Additional components supplied on the 454 assembly included a flexplate, an HEI distributor with plugs, plug wires from ProComp, and a new damper. The oiling system included a new standard (or high-volume) oil pump with a brazed pickup and a heavy-duty drive, a new oil filter, and a truck pan. About the only thing missing from the motor was a carburetor. For our dyno session, we installed a Holley 750 HP-series four-barrel, but similar power numbers can be made with a less expensive version. As indicated, we prelubed the motor using 10W-30 Lucas conventional oil, the high-zinc break-in lube, and an electric drill. The valves were adjusted and the motor was run through a computer-controlled break-in procedure (for the new cam and rings to seat properly). After break-in, we made a few pulls, adjusted the timing to 40 degrees total, and dialed in the air/fuel curve. With the tuning completed, we were rewarded not with 400 hp as advertised, but with peak numbers of 446 hp at 4,900 rpm and an impressive 542 lb-ft at 3,600 rpm. Torque production from the low-bucker exceeded 500 lb-ft from 2,800 rpm to 4,600 rpm-that should annihilate some asphalt. Even with the expense of a carburetor, figure on less than $3,000 for a 400hp big-block Chevy package that delivers more than advertised, making this 454 good for some late-night Camaro fun.
Displacing a true 461 ci thanks to a 0.030 overbore, the Demon 400hp 454 delivered more than advertised by producing 446 hp at 4,900 rpm and an impressive 542 lb-ft at just 3,600 rpm. Torque production from the big-block exceeded 500 lb-ft from 2,800 to 4,600 rpm. The Demon 454 belted out 490 lb-ft way down at 2,500 rpm and never produced less than 400 lb-ft. That, my friends, is why big-blocks rule. This motor would be equally at home in an RV, truck, or performance street machine and (if 450 hp and 542 lb-ft aren't enough) would make an excellent starting point for a more serious buildup.
PARTS LIST DESCRIPTION PN SOURCE PRICE Demon Engines 400hp 454 DE454/400 Demon Engines $2,650.00 Holley 750 HP carb* 0-80528-1 Jegs 643.00 Big-block water pump 58141 Rock Auto 21.75 E3 performance plugs E340 Summit Racing 47.92 Break-in oil additive 10063 Summit Racing 15.99 Percy's Adjust-A-Jet PHP-15005 Summit Racing 89.95 Total $3,468.61 *What? We like the Holley 750 HP. Use that crusty 3310 if you want to. See if we care.
