Proven Horsepower Engine Combinations - 500hp Engine Combos

On JGM's dyno, this 466 easily... 

   

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On JGM's dyno, this 466 easily blew past 500 hp, but it also made a spine-bending 565 lb-ft of torque at a loafing 4,400 rpm.

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 1 3/4-inch headers on this beast along with a good 2 1/2-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
Torrance, CA
800/416-8628
edelbrock.com

Jim Grubbs Motorsports
Valencia, CA
661/257-0101

Holley Performance Products
Bowling Green, KY
270/781-9741
holley.com

Adding cubic inches is the... 

   

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Adding cubic inches is the easiest way to make more normally aspirated power. A larger engine will almost always make more average torque and horsepower with a given cylinder head and cam combination. This is why everyone builds 383 Chevys versus 355s.

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 1 3/4-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.

Air Flow Research
Pacoima, CA
877/892-8844
airflowresearch.com

Comp Cams
Memphis, TN
800/999-0853
compcams.com