Chevy 350 Engine - Crate This!

Our combo this month was a GMPP crate engine producing 290 hp at 5,100 rpm and 326 lb-ft of torque at 3,750 from the factory.

With its 8.5:1 compression, four-bolt block, and small street cam, this piece is a true 87-octane-burning mill that'll put new life back into any Chevrolet. While the engine would serve as a great mule for the average commuter, we're about to showcase the untapped potential waiting to be released.

The Plan
Our engine design started by addressing several key areas of the engine where GM knowingly sacrificed potential power for a smooth idle, low emissions, and low-octane operation. The factory cylinder heads may be ideal for a daily driver, but they are definitely not meant to make big power. Our plans called for a set of GMPP's newest Fast Burn 210cc aluminum cylinder heads. Their ports offer superior airflow characteristics with vastly improved intake and exhaust runners, while the new Fast Burn combustion chambers ensure that the incoming air/fuel mixture will burn efficiently. These heads alone are so good we decided to bolt them onto our crate engine using an Edelbrock Air Gap Performer RPM and a 650-cfm Holley HP carburetor with mechanical secondaries. Along with these tried-and-true induction pieces we also used an MSD billet distributor, a 6AL ignition box, and high-performance 8.5mm wires to make sure our cylinders stayed lit during the upper-rpm flog. The factory heads feature 76cc combustion chambers, which were hurting power with an 87-octane-compromising 8.5:1 compression ratio. The new GMPP heads feature smaller, 62cc combustion chambers that would raise the compression of our engine to a 91-octane-friendly 9.9:1. This alone would be worth nearly a 3-percent power gain, not to mention how much more power would come from the Fast Burn chamber design and improved port layout.

The GMPP crate engine arrived accessory-free, requiring several supporting pieces, including an oil filter and bracket, cylinder-head water plugs, spark plugs, and a harmonic balancer. The only dilemma we ran into while putting our engine on the dyno was that the Edelbrock intake manifold had some interference issues with the stamped-steel valve covers that came on our engine. We could have milled the factory valve covers to fit, but with our tight schedule, swapped them out for a set of Comp Cams aluminum tall-body valve covers and opted to utilize an electric water pump and 131/44-inch dyno headers with no other accessories. We also added 5 quarts of 20W50 Lucas oil and a bottle of Comp Cams break-in lube to ensure our new hydraulic flat-tappet camshaft would break in properly. It's important to note that GMPP does not break its engines in before they arrive, which makes it critical for the end user to do so with hydraulic flat-tappet applications.

Our Fast Burn aluminum heads...        read full caption Our Fast Burn aluminum heads not only weigh nearly half that of an iron heads, but they made 44 hp and 27 lb-ft of torque more out of the box than a stock head.

Both the stock and new head...        read full caption Both the stock and new head applications wore an Edelbrock Performer RPM Air Gap intake manifold to promote the best power possible. The factory stamped-steel valve covers had interference issues with this manifold, so we added a set of Comp Cams tall-body covers to go along with the top-end aluminum theme.