CHUMP CHANGE
Car Craft|March 2020
Hunk-O-Junk Big-Block, Part 5: The eBay Turbo Test!
Richard Holdener
CHUMP CHANGE

It seemed like a match made in heaven. Take one modified, junkyard 454 and add some cheap boost from a $163 eBay turbo. Did it work? Sure. Did it work perfectly? Let’s take a look! The project actually started quite some time ago after we pulled a Gen 6 454 from the engine bay of a 1-ton Suburban. The Pick-a-Part special was then prepped for dyno use by replacing the factory EFI with a carbureted, dual-plane intake and non-computer-controlled distributor. Back in Part 1, the carbureted (but otherwise stock) 454 produced 378 hp at 4,700 rpm and thumped out 482 lb-ft of torque at 3,500 rpm. Our shortcut to power came in Part 2, with the installation of a Holley Sniper nitrous system. Nothing adds an extra 125 hp quicker (or easier) than a nitrous kit, and run with 125hp jetting, the 454 thumped out 519 hp and 646 lb-ft of torque.

The next step was to perform a cam and valve spring swap. Installation of the Comp XR276HR cam and 26120 springs resulted in a jump in power from 378 hp and 482 lb-ft to 427 hp and 504 lb-ft. The final upgrade came in Part 4 where we added a set of Dart Pro 1 275 (oval-port) heads and a custom Comp cam, which pushed the peak power numbers up to 503 hp and 492 lb-ft of torque.

After upgrading the 454 with the Dart heads and custom Comp cam (0.561 lift, a 233/239-degree duration and 118-degree LSA), the 454 still suffered slightly from low compression. The added chamber volume of the Dart Pro 1 heads reduced the static compression below 8.0:1. While not ideal for naturally aspirated power, it was just begging for boost. Knowing this, we decided it was high time the 454 received some positive pressure.

This story is from the March 2020 edition of Car Craft.

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This story is from the March 2020 edition of Car Craft.

Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.