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496 Chevy Big Block Build - Pump Gas Stump Puller

How About 598 LBS Of Twist On 91-Octane Gas With Street Manners?

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Behold the fruits of our labor; 496 cubic-inches of Chevy big-block goodness. Finishing off the build is a Weiand aluminum water pump (PN 9242, $99.95) and a set of very sweet Doug's headers (PN D320). Doug's has been doing headers since 1958 and these hand-built, mandrel-bent tubes are a work of art. Featuring two-inch primaries and 3.5-inch collectors, they are tuned with the proper size and length to efficiently remove all the spent gases from each cylinder. This reduces pumping loss and the result is more power and torque. The ceramic coating is for more than just looks. It can drastically lower engine bay temps and that equates to more power. Since this engine is externally balanced, Eagle supplied the balancer along with a properly worked-over flexplate. Keeping the valvetrain covered up, and looking great, is a set of fabricated valve covers from Spectre Performance (PN 5041, $136.99) and a set of Fel-Pro molded silicone and steel core gaskets (PN 1635, 42.95) inhibits leaks.

We loaded up the engine and took it over to Westech for a little time on its Superflow 901 dyno. After installing a K&N oil filter and dropping in seven quarts of Lucas oil, Westech dyno guru, Steve Brule, fired up the big-block and started making pulls and adjusting timing and fuel. After a few tries we nailed down a best pull of 593 hp at 5,900 rpm and 595 lb-ft of torque at 4,500 rpm. This was at 38 degrees of timing and 71/83 jets (8.5 power valve). Try as we might, we just couldn't sneak over the 600 mark. Out of curiosity we bolted on a one-inch open spacer and the numbers squeaked up to 596 hp at 5,900 and 598 pounds of twist at 4,500. Even though the peak was up just a touch the lower end of the pull saw a more significant gain.

If we wanted to jump over the magic 600 mark we decided we would need stiffer valve springs, 1.8 rockers, and possibly a single plane intake. Of course we could always go with a more aggressive cam, but that would veer away from our goal of building an easy to live with street engine. Besides, we're going to have a hard enough time hooking up this much power once we find a car to stuff it into.

496 Dyno Numbers
Two-inch Long Tube Headers, 1-inch spacer
TQ HP
3600 583.7 400
3700 582.4 410
3800 586.7 424
3900 588.0 437
4000 588.1 448
4100 588.9 460
4200 592.8 474
4300 594.0 486
4400 595.3 499
4500 598.1 512
4600 595.7 522
4700 592.6 530
4800 592.8 542
4900 589.3 550
5000 588.0 560
5100 585.0 568
5200 580.4 575
5300 576.0 581
5400 567.8 584
5500 556.5 583
5600 545.0 581
5700 539.6 586
5800 538.3 594
5900 530.2 596
6000 516.8 590
6100 507.1 589
6200 499.5 590
6300 491.4 589
SOURCES
ARP (Automotive Racing Products)
8-00/-826-3045
www.arp-bolts.com
MSD
El Paso
TX  79936
915-857-5200
www.msdignition.com
Competition Cams
Memphis
TN
8-00/-999-0853
compcams.com
Outlaw Racing Engines
909-931-4612
Clay Valley Racing (CVR) Patriot Performance
Rainbow City
AL
888-462-8276
patriot-performance.com
Doug's Headers
909-788-4878
www.dougsheaders.com
Performance Stainless
Eagle Specialty Products
Southaven
MS
6-62/-796-7373
eaglerod.com
Spectre Performance
spectreperformance.com
Fel-Pro/Sealed Power Torco
www.torco.com
Holley/Weiand
2-70/-781-9741
www.holley.com
Westech Performance
9-09/-685-4767
Milodon
2250 Agate Ct.
Simi Valley
CA  93065
805-577-5950
www.milodon.net
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