Boneyard Boost: Vortech 454

Words And Photos: Richard Holdener

The problem with making more power is that cost and performance often go hand in hand. The greater the power gains, the bigger the budget. Project Boneyard Boost was one of those rare occasions where we got to apply a massive infusion of power to a motor that cost next to nothing. The proper application of boost to any motor is never inexpensive, and our Vortech YSI supercharger was not what could be considered low-buck, but it was epic in its effectiveness. Thanks to a maximum impeller speed of 65,000 rpm (racers go even higher) and a peak efficiency rating of 78%, the Vortech YSI was capable of supporting over 1,200 hp at 30 psi. The budget portion of the equation came from a 7.4L Gen VI big-block Chevy straight out of the local wrecking yard. Forget the typical race-motor build up, Boneyard Boost was all about force feeding some tired, high-mileage workhorse we purchased for the paltry sum of $500 ($250 on half price sale weekend!).

In our quest to locate a suitable 454, a typical rip to the wrecking yard revealed at least three of the four available big-block combinations. We immediately checked the latest 8.1L off the list due to lack of availability and parts cross over. Though larger than the previous 7.4L models, the unique 8.1L could not utilize the amazing array of performance parts available for the previous three conventional big-block models. This left us with Mark 4, Gen V and Gen VI big blocks to choose from, any of which would work for this project. In the end, we selected a 1999 Gen VI 454 and pulled it from its home in the engine bay of a 1-ton work truck. The L29 454 was originally rated at 290 hp and 440 lb-ft of torque thanks to a combination of fuel injection, large oval-port heads (to replace the peanut ports used in the previous Gen V motors) and a slightly higher static compression ratio. The heads used on the L29 combined the large oval intake ports with small (100 cc) combustion chambers to produce a slightly higher (than the Gen V) 9.0:1 compression. The compression was plenty low for use with the blower, but the extra power it provided would eventually be multiplied by the boost.

After selecting a motor, we set about making the necessary changes for our test. We removed the factory EFI injection, and replaced it with simple carburetion. For this test, the motor was configured with an Edelbrock RPM Air Gap intake and Holley 750 carburetor. To further improve power, we also upgraded the stock hydraulic roller camshaft with an XM284HR from COMP Cams that offered .547 lift, a 230/236-degree duration split and 112-degree lsa. To allow the motor to rev cleanly to 6,000 rpm under boost, the cam upgrade was teamed with a new set of beehive valve springs. Before adding boost, the boneyard big block was run in normally aspirated trim and produced 427 hp at 5,500 rpm and 476 lb-ft of torque at 3,900 rpm.

After the normally aspirated testing, we replaced the 750 Holley with a dedicated blow-through 850 Holley carburetor from Carb Solutions Unlimited (CSU) and installed the Vortech supercharger kit. In addition to the powerful YSI supercharger, the kit included a cog-drive system to eliminate belt slippage under boost. Vortech supplied a pulley combination that included an 80-tooth crank pulley and 32-tooth blower pulley which provided a drive ratio of 2.5:1. This combined with the internal step gearing and maximum engine speed of 6,000 rpm to produce a peak impeller speed of 51,700 rpm, well below the listed maximum of 65,000 rpm.

After configuring a discharge tube and adding some race fuel, we slowly supplied boost to the boneyard big block. We wanted to make sure the air/fuel and timing curves were spot on before running the supercharged monstrosity in anger. The ignition timing was dropped to 21 degrees and after adding a few jets to the carburetor, we were rewarded with some serious power. Configured with our pulley combination, the YSI spit out a peak boost pressure of 19.1 psi where the boosted big block produced 791 hp and 713 lb-ft of torque. The great thing about using a blow-though carburetor combination is the intercooling effect you get from the introduction of fuel. Temperature measurements taken before and after the carburetor revealed that the fuel cooling dropped the intake charge temperature from 235 degrees (before the carb) down to 120 degrees (after). Despite the impressive cooling powers of the carburetor, we were still concerned about the elevated charge temps going into the carburetor. In an effort to further drop the inlet air temps, we installed a makeshift air-to-water intercooler.

Truth be told, Vortech offered a number of Maxflow Aftercooler systems but we selected an intercooler core we had on hand for testing. The single core from CXRacing featured 3.5-inch inlet and outlets and had been tested previously at over 1200 hp and 25 psi. Using 3.5-inch aluminum tubing from CXRacing, we configured the intercooler between the YSI supercharger and the blow-through carburetor bonnet. We also took the liberty of installing a Race-Port blow-off valve from Turbo Smart. With the intercooler assembly in place, we once again ran the blown big block in anger with amazing results.

The intercooler did indeed drop the inlet air temps before the carburetor from 248 degrees to 111 degrees and the cooler charge dramatically improved the power output. The peak numbers jumped from 791 hp and 713 lb-ft with no intercooler to 847 hp and 761 lb-ft with the intercooler. The cooler charge air (plus tubing length and bends) dropped the peak boost pressure from 19.1 psi down to 17.7 psi. There was plenty of power left in the YSI, but at 847 hp we couldn’t help but be amazed at the extra strength GM put into the design of their 290-hp big block. Check back with us as we plan on adding a set of Brodix Race Rite aluminum heads to the mix in Part 2 of Project Boneyard Boost.

https://youtu.be/Fy6C0pznjMw

Sources

COMP Cams
compcams.com

CSU
csucarbs.com

CXRacing
cxracing.com

Edelbrock
edelbrock.com

Holley/Hooker/Weiand
holley.com

Turbo Smart
turbosmartusa.com

Vortech Superchargers
vortechsuperchargers.com

About the author

PPN Editor

Power & Performance News is the source for news, tech and products that help you get more performance from your vehicle. If powertrain performance projects and hardcore technical content are your interest, Power & Performance News is the publication designed for you. Our acclaimed editorial staff covers all aspects of engine and driveline upgrades with a mission of presenting information that is both interesting and achievable for the “average car guy”.
Read My Articles

Hot Rods and Muscle Cars in your inbox.

Build your own custom newsletter with the content you love from Street Muscle, directly to your inbox, absolutely FREE!

Free WordPress Themes
Street Muscle NEWSLETTER - SIGN UP FREE!

We will safeguard your e-mail and only send content you request.

Street Muscle - The Ultimate Muscle Car Magazine

streetmusclemag

We'll send you the most interesting Street Muscle articles, news, car features, and videos every week.

Street Muscle - The Ultimate Muscle Car Magazine

Street Muscle NEWSLETTER - SIGN UP FREE!

We will safeguard your e-mail and only send content you request.

Street Muscle - The Ultimate Muscle Car Magazine

streetmusclemag

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...


fordmuscle
Classic Ford Performance
dragzine
Drag Racing
chevyhardcore
Classic Chevy Magazine

Street Muscle - The Ultimate Muscle Car Magazine

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

  • fordmuscle Classic Ford Performance
  • dragzine Drag Racing
  • chevyhardcore Classic Chevy Magazine

Street Muscle - The Ultimate Muscle Car Magazine

streetmusclemag

Thank you for your subscription.

Thank you for your subscription.

Street Muscle - The Ultimate Muscle Car Magazine

Thank you for your subscription.

Thank you for your subscription.

Loading