C3 Big-Block Engine Swap - Big-Block Party

Part 2: Our injected Rat motor begins to take shape

Paul Sisia Sep 1, 2011 0 Comment(s)
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Lamar and Rob are the father-and-son team at Lamar Walden Automotive (LWA). Lamar is an ex-GM engineer and a well-known authority on Chevrolet big-block engines. Rob has been working full-time in the family business for the last 22 years. The pair just celebrated 40 years at their current location, and their engines have been run in everything from circle track and Pro Stock racing to speed boats and even NASCAR.

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Lamar is arguably the most knowledgeable person on the planet when it comes to Chevy's 409 big-block—he designed the new all-aluminum 409 and 509 for Bill Mitchell's World Products—and he holds the record for the most powerful 409 ever built. He's also notched 31 wins in Pro Stock behind the wheel of his own car, powered by a self-built small-block Chevy. When it came to selecting a shop to assemble our engine and dyno the finished product, Lamar and Rob Walden were at the top of the list.

The LWA facility is a feast for the eyes, with old-school carbureted monster motors sitting alongside modern fuel-injected hardware. There are engine components, machining equipment, and boxes of high-performance parts everywhere. The facility is also a complete machine shop with three CNC machines, a SuperFlow bench, and an engine and chassis dyno as well. Suffice it to say that "All baking is done on the premises."

When our conversation turned to selecting a cam, Lamar mentioned that he knew Gordon Holloway at Comp Cams. Turns out Lamar was Comp's very first customer back in the early '70s. On that note, we decided to stop asking questions about lift and duration and just have Lamar and Rob spec the cam directly with Holloway. But before they did that, they flowed the AFR heads on their SF600 flow bench and compared them with the flow numbers provided by AFR. They were spot on.

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When everything was taken into consideration, including the rear gear ratio, projected engine speed on the highway, vacuum requirements, and more, Rob ordered a custom-ground 0.600/0.610-inch lift, 230/ 236-degree duration, 112-degree LSA hydraulic roller cam. This cam is designed to make power from 1,800 rpm all the way to 6,000 rpm, and it will be happy just cruising along at 2,200-2,400 rpm on the highway. We also ordered Comp's Ultra Pro Magnum roller rockers, pushrods, timing chain, and gearset. Finally, Lamar and Rob recommended a FAST EZ EFI Management System to maximize the power and efficiency of our big-block. (It's the same system the Waldens use on their own dyno.)

We ordered the FAST EZ EFI Multiport System along with a FAST idle air control valve, water- and air-temperature sensors, map sensor, fuel regulator, and all the necessary connections. Summit Racing shipped us a set of FAST 60-lb/hr fuel injectors, Hedman ceramic-coated 2-inch headers, a Summit-brand high-torque starter, and a complete MSD ready-to-run ignition system to put some fire in the hole.

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To Top It All Off
F&B Throttle Bodies is pretty well known in Mopar circles, since the company builds and sells triple-throttle-body, fuel-injected, "6-pak" systems for 440 Challengers and 'Cudas. However, designing and building a 3x2 throttle-body system for a big-block Chevy is a bit more difficult because no one currently manufactures an appropriate aluminum intake. One option is to scour eBay and Craiglist to find an original Tri-power intake, but the asking price is usually prohibitive—between $1,500 and $2,000.

Bruce Bridges, the president of F&B, offered a better idea: Start with an old-school, high-rise, dual-quad aluminum intake and modify it to accept the three throttle bodies. His logic was clear. The original '69 427/435s required a very-low-rise intake in order to fit under the stock Corvette hood. This intake wasn't designed for performance at all, but rather to fit the packaging concerns of the engine compartment. Using F&B's custom billet throttle bodies, which are shorter than the original Holley two-barrel carbs, allowed us to use a taller intake that could produce more power. In theory, our modern fuel injection, combined with a high-rise aluminum manifold, should prove almost twice as good as the original setup.

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