GM Performance Parts 350ci/330HP Crate Motor Build

We Get More Power Out Of A GMPP Crate Motor With Goodies From Brodix, Lunati, And Speed-O-Motive.

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John Barkley, one of our associates here at Super Chevy, just recently did a little horse-trading and ended up with a fresh GM Performance Parts (GMPP) 350ci/330HP crate motor. He is an avid hot rodder and was a successful drag racer for many years (he even has a Wally in his trophy case from winning the Stock Eliminator class at the 1983 Winternationals). John is constantly building something, and his most recent project is a '66 Bel Air that could use some more power under the hood. He plans on using the car for cruising and light track duties. Even though the GMPP 330hp crate motor would motivate his land yacht of a car just fine, we would rather have the big ship run more like a small flat bottom drag boat.

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We set John loose with the task of finding a solid upgrade for his engine that didn't require special machining or messing with the rotating assembly. He contacted Brodix for one of the company's top end kits, to take out the guesswork when it comes to finding components that work with each other. Brodix combines a set of the company's IK (Iron Killer) 180cc aluminum heads with a matching dual plane intake manifold, and all the little things like gaskets and hardware needed for the swap.

The heart of the Brodix top end kit are the heads; these feature ultra casting, 180cc intake ports, and 64cc combustion chambers that allow the use of several types of fuels. All these improvements over the stock heads are in place to increase the airflow. The more air the engine can ingest, the more power it can make. There are a bunch of options Brodix offers on these heads like 58-74cc CNC chambers, and just about anything else your deviant mind can think up, so keep that in mind when ordering. The Brodix kit comes with a dual plane intake big enough to support the heads, and for a small extra fee match ported as well.

For the valvetrain, John went with components from Lunati's Voodoo line, most notability a solid roller cam. John has always used hydraulic cams in his street motors, but wanted to try a solid roller this time. The cam spec's out at 0.555-int./0.566 exh. lift, 261 int./267 exh. advertised duration, 231 int./237 exh. duration at 0.050, with a 110-degree lobe center. He coupled the cam with a set of vertical bar roller lifters and 1.5 ratio Voodoo aluminum roller rockers. John went with this combo to be safe, not knowing how much piston to valve clearance it was going to have with the GMPP stock pistons. During testing we found this cam to be too small, but more on that later.

To feed the new heads, one of Holley's 750cfm Ultra Double Pumper street/strip carbs was tasked with fuel delivery. It's a 4150 design, but has black anodized billet aluminum metering blocks and base plate, mechanical secondaries, and surprisingly enough, an electric choke-not something normally found on a double pumper. To provide the spark, a ready to run billet HEI distributor from MSD was called to action. Since firewall clearance is not an issue, going with the coil-in-cap design and modern electronics were a no brainer. To assemble all of John's goodies and tune the engine on the dyno, we enlisted the help of the Speed-O-Motive crew in Covina, California. Don't get us wrong, we made John get his hands dirty on this project, but Jeff Strech from Speed-O-Motive also got involved. It was like watching an NHRA pit crew ripping down a motor between runs.

FLOW CHART (CFM@28-INCHES H2O)
FOR THE IK (IRON KILLER) 180CC HEADS
Valve Size Lift 0.200 0.300 0.400 0.500 0.600
2.02 Intake 138 188 234 243 245
1.60 Exhaust 112 149 167 175 178

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