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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

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.

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.

Comp Cams Inc.
3406 Democrat Road
TN  38118
Pro Comp Electronics
605 S Milliken Avenue
Unit A
CA  91761
Hooker Headers
704 Highway 25 South
MS  39730
L&R Automotive
13731 Bora Drive
Sante Fe Springs
CA  90670
Demon Engines
Sante Fe Springs
Probe Racing
2555 West 237th Street
CA  90505
By Richard Holdener
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