383-Inch/Supercharged Combination Engine - Complete Engine Build and Performance Testing

383 Supercharged Engine Camaro Z28 Convertible

More Power Awaits Us In KansasThis is the second installment of our build-up coverage and testing of a new, 383-inch/supercharged combo destined for our '96 Z28 convertible.

We sent the Camaro out from sunny Southern California to the fringes of industrial Flint, Michigan, to the high-end speed shop/tuning facility of Hardcore Racing. There, the tired 350 and its early-model ProCharger were dropped out of the car in preparation for a Scoggin-Dickey-supplied 383 and fresh supercharger.

Upon arrival at Hardcore Racing, some changes were made on the Scoggin-Dickey short-block to accommodate the supercharger. This included swapping out the 10.4:1 pistons for 9.1:1-compression slugs. Also, a more blower-appropriate camshaft was supplied by Crane Cams. Hardcore's Eric von Hentschel handled all of the engine work for this project.

Capping off the 383 is a complete LT4 head/intake kit from Pace Performance Warehouse and a trick TPIS billet throttle body. The kit is based on the LT4 engines found in a few limited edition '96 Corvette models. The upgrades include the famed, higher-lift "Hot" camshaft, 1.6-ratio roller rockers, high-flow aluminum cylinder heads, springs, and the signature red-painted intake manifold with raised intake runners.

The starting point for our project was this Scoggin-Dickey-supplied 383 short-block. It's a custom-built engine that S-D offers, not simply a GM long-block assembly. It's got splayed four-bolt mains and a Lunati 4340 forged crank on the bottom end. To accommodate the supercharger, lower-compression 9.1:1 pistons and a blower-friendly cam were installed.
The starting point for our project was this Scoggin-Dickey-supplied 383 short-block. It's
The LT4 intake is instantly identifiable because of red color. It also has raised intake runners, compared to the LT1 intake. Note here, too, the aluminum, roller-tip 1.6-ratio rocker arms that also are part of the LT4 setup.
The LT4 intake is instantly identifiable because of red color. It also has raised intake r
Breathing chores are handled by a complete LT4 conversion kit from Pace Performance Warehouse, which included a pair of aluminum LT4 cylinder heads, which boast 195cc intake runners and 2.00/1.55 valves.
Breathing chores are handled by a complete LT4 conversion kit from Pace Performance Wareho

Like the 383 short-block, a few changes were required to accommodate the LT4 to the new combination, including valvespring mods, handled by Crane Cams. (See the Feb. '05 issue for more details.)

When all fasteners were finally torqued to spec, the new 383 was pushed over to Hardcore's engine dyno for some break-in time.

Waiting On A D-1SC
The supercharger that already was on the engine, when the Camaro rolled into Hardcore Racing, was an older-model P-1 from ATI ProCharger. It performed well for the old combination and, initially, we were going to reuse it on the 383.

Capping off the long-block assembly is a new, 58mm throttle body from TPIS. This replaces the 350 engine's stock throttle body.
Capping off the long-block assembly is a new, 58mm throttle body from TPIS. This replaces
Before going nuts with the supercharger, we wanted to know what the engine did in normally aspirate mode. The results-340 hp at 5,300 rpm and 280 lb-ft at 3,900 rpm-didn't seem right for an LT4-fed 383, but the new cam and lower-compression pistons are designed for the supercharger, not NA power. Some tests were performed with the original blower, but the tuning wasn't right, so the testing was called off until we could secure a new D-1SC system.
Before going nuts with the supercharger, we wanted to know what the engine did in normally

Things changed, however, when the supercharger was bolted to the engine on Hardcore's engine dyno. With the higher-volume 383 and previous combination's tuning, the performance just wasn't what we expected-or wanted. The engine made 454 hp and 476 lb-ft, but maxed out with about 6 pounds of boost. Not bad, but certainly not great, either.

While the combination could have been made to work, the existing tune simply wasn't compatible with the increased airflow requirements of the 383-cid displacement and higher flowing LT4 heads. To put it simply, the old tune was good for the old 350 engine, but not for the new 383.

It seemed like a good opportunity to upgrade to ProCharger's D-1SC supercharger. Unfortunately, the castings for the D-1SC weren't ready to meet our deadlines for this issue. Rather than have the car hold down Hardcore's shop floor, Dan Jones, from ProCharger, offered to bring the car to the company's Kansas headquarters so that we could jump on it as soon as the blowers were ready. ProCharger's engineers would also be able to lend their tuning expertise to ensure that the system made optimal power.

The Hardcore crew bolted up the engine (with the old blower installed) and made the car ready for ProCharger's pick-up. And that's where we leave for this issue.

Look to a future issue as we extract all the power we can from our new, supercharged 383. If you ever thought LT1 performance was yesterday's news, you ain't seen nothing yet!

With the engine dyno work completed, attention turned to re-installing the engine. We were able to grab one of the first tubular K-member kits from Granatelli and decided to install it, along with the engine.
With the engine dyno work completed, attention turned to re-installing the engine. We were
The Granatelli K-member is a simple, bolt-on replacement for the original engine cradle. It is built from super-solid 1.15-inch-diameter steel tubing and offers a considerable weight savings over the stock piece. It accepts stock or aftermarket A-arms and other suspension parts, while also available with solid motor mount provisions for the serious racing application.
The Granatelli K-member is a simple, bolt-on replacement for the original engine cradle. I
Hardcore Racing mounted the steering rack to the new K-member, as well as the other front suspension components. Check out the clever "shock brace" that holds the suspension upright prior to installation in the vehicle.
Hardcore Racing mounted the steering rack to the new K-member, as well as the other front

Here's the engine assembly installed on the Granatelli K-member, ready for installation in the car. Check out the sturdy mounting plate for the D-1SC supercharger, too. The big blower would create some exhaust routing issues, but more on that in the next issue.
Here's the engine assembly installed on the Granatelli K-member, ready for installation in
With the temporary shock brace removed, the front suspension droops as it is positioned beneath the chassis and readied for installation.
With the temporary shock brace removed, the front suspension droops as it is positioned be
With the engine/cradle assembly basically attached, the car was raised so that the chassis components and other connections could be tightened.
With the engine/cradle assembly basically attached, the car was raised so that the chassis

Here, the engine and Granatelli Motorsports suspension cradle/K-member are bolted up.
Here's a top-end shot of the installed 383 engine. The red LT4 intake provides a dramatic and no-mistakes-about-it look under the hood. From here, the car goes to ProCharger's Kansas facility for the D-1SC and tuning.
Here's a top-end shot of the installed 383 engine. The red LT4 intake provides a dramatic

SOURCES
Hardcore Racing	ATI ProCharger 14801 W. 114th Terr. Lenexa KS 66215 913-338-2886 www.procharger.com
Scoggin-Dickey Parts Center Lubbock TX N/A www.sdparts.com	Granatelli Motorsports 18551 Topham St., Unit J Reseda CA 91335 818-996-2753 www.granatellimotorsports.com
Pace Performance Warehouse 430 Youngstown-Warren Rd. Niles OH 44446