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Oldsmobile 468CI - 500hp Engine Combos

Anyone Can Build

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Ford 466ci

It doesn't get much easier to make 500 hp when you start with a giant motor. The Ford 460 is an easy jump, and most of the parts are a one-stop-shopping expedition if you're dialed into the Edelbrock connection. Jim Grubbs Motorsports built a 0.030-over 460 Ford that we detailed and tested in the Feb. '06 issue ("Easy 500 HP From the Ford 460.") After later flogging a bigger cam, we discovered that Edelbrock really did its homework on this gem. The Performer RPM package does exactly as advertised, making 514 hp at a loafing 5,400 and 565 lb-ft of torque at 4,400 rpm.

Start with a good, sealed-up short-block with at least 9.5:1 compression (we used Speed-Pro forgings). The Edelbrock Performer RPM flat-tappet hydraulic cam measures 234/244 degrees at 0.050-inch tappet lift with 0.556/0.581-inch lift with 1.7:1 rocker arms and a lobe separation angle of 108 degrees. We used a set of Harland Sharp aluminum roller rockers to tickle the valves. Head selection is also easy with a set of Edelbrock Performer RPM heads that offer 2.19/1.76-inch valves and good flow right out of the box. Grubbs just put a set of these heads on a much more aggressive 642ci stroker Ford 460 and made over 650 hp.

Clearly, the Edelbrock Performer RPM dual-plane intake was a no-brainer for this combo, along with a 750-cfm carburetor that was worth plenty of airflow to make the 500hp number. The trick is to make sure you can fit 134-inch headers on this beast along with a good 212-inch exhaust system that minimizes restrictions on the hot gas side. Larger headers only hurt the average power with no plus on the horsepower end. Set the timing at 36 degrees and let 'er rip!

Edelbrock Air Gap intake 7566 Summit Racing $329.88Edelbrock RPM 460 intake 7166 Summit Racing 205.95Edelbrock RPM CJ heads 61649 Summit Racing 959.50 ea.Edelbrock Performer cam kit 2167 Summit Racing 137.88Harland Sharp 1.73 rockers S4005 Summit Racing 215.88ARP head bolts 155-3603 Summit Racing 105.95Holley 750-cfm carb mech. 0-4779C Summit Racing 396.88

Edelbrock; Torrance, CA; 800/416-8628;
Jim Grubbs Motorsports; Valencia, CA; 661/257-0101
Holley Performance Products; Bowling Green, KY; 270/781-9741;

Small-Block Chevy 383ci

While the first-generation small-block Chevy enjoys the fruits of more horsepower tuning than probably any other engine on the planet, it also suffers from the limitations of its design. Since cylinder-head flow is limited compared with the Gen III engine, we chose to build a 383 with a few more inches to make up for its airflow limitations.

Expect to step up to a good aluminum head like the fully CNC-ported AFR 195 to flow enough air to make excellent torque and still clear the 500hp cutoff. We know AFR has an all-new set of port designs that might be out by the time you read this, and the new AFR 195 is a gangbuster. We've seen the flow numbers on the prototypes and they are killer. If you're willing to be patient for a few months to get heads that can flow 280-plus cfm, that should be worth the wait.

But even if you use the fully ported current version AFR 195 at around 260 cfm, this head will still step up past the 500hp limit. For a camshaft, we're going with a Comp mechanical roller XR274 grind that will spec out at 236/242 at 0.050-inch tappet lift with 0.564/0.570-inch lift with a 110-degree lobe separation angle. This cam will require some stout valvesprings, a good set of roller rockers like Comp's Hi-Tech series, and good pushrods. Combine this cam with 10.5:1 compression, a Victor Jr. single-plane intake manifold, a Holley 0-4779 750-cfm double-pumper carb, and a set of 134-inch headers, and you have a package that should be worthy of 515 hp at 6,000 rpm and will still make excellent torque with 510 lb-ft at 4,400 rpm. Then your biggest problem will be figuring out how to make the tires stick.

Parts List

DESCRIPTION PN SOURCE PRICEAFR 195cc heads 1038 AFR $1,324.00Comp XR274 roller cam 12-770-8 Summit Racing 245.95Rockers, 1.6 Hi-Tech 1105-16 Summit Racing 407.69Edelbrock Victor Jr. intake 2975 Summit Racing 185.88Holley 750 mech. sec. carb 0-4779C Summit Racing 399.95

Air Flow Research; Pacoima, CA; 877/892-8844;
Comp Cams; Memphis, TN; 800/999-0853;

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