Big-Block Performance Parts - MAX-ing Out

Holley designed this intake manifold specifically for the EFI demands on the big-block. With a few exceptions, most of the EFI setups we've seen have been carbureted designs revamped with EFI components. This purely dry-flow design excels at delivering air to the runners without concern for fuel.

Note the symmetry from front to rear and from side to side. It's not a two-piece intake; we cut it this way to show you what's going on. The large peak directly centered on the plenum floor is the result of much experimentation with shapes and heights. Holley does not recommend using a carburetor on this intake, as the peak will not promote fuel delivery.

Carburetor fans are already familiar with the Weiand Stealth intake. It's been proven as one of the best power producing dual-planes on the market, and makes a great choice for the SysteMAX. The big runner design has great volume, and the length of the runners allows for good bottom-end response. It's a great all-around design for carbureted big-inch street engines.

Besides the obvious weight savings, the Holley cylinder head offers many advantages over the GM parts that deliver on the 502. The most dramatic, beyond larger runner sizes, is the chamber shape. The wall angles and kidney bean chamber shape are extremely efficient on the Holley head (right).

Systemax - The stock Gen VI 502 is no slouch right out of the box, producing 450 hp at 5,250 rpm and 550 ft-lbs of torque at 3,500 rpm. This is a very streetable engine, and all of the bottom end parts are stout. Addition of the SysteMAX components (with EFI) turned up the wick by a full 105 ponies (to 555 hp at 5,600 rpm) and cranked up the grunt to 564 ft-lbs at 4,700 rpm. The beauty of the SysteMAX parts is that streetability was not affected. Idle was nice and rumpity at 850 rpm, but stable enough to produce good vacuum. Throttle response was very crisp, and there was no off-idle stumble.

The EFI system that comes with the big-block SysteMAX package is one of Holley's new multi-point setups. It's a recent design that you probably haven't seen before, and it will also be available separately from the SysteMAX package. The software is great, making it very simple to program. Holley supplies a programming map with the SysteMAX that produced the numbers seen in the accompanying chart. If you're running a 502, it'll be right on.

Dave Thomas drives the new DTS dyno at Holley's Tech Center. He's worked extensively to refine the big-block SysteMAX for outstanding all-around results. He told us "Idle quality and vacuum are just as important to us as horsepower numbers. We wanted a complete system that would do everything well, and we're very confident in our package. We have a great team here, and all of our customers will benefit from the amount of research we've invested into matching these components."