Crate LT1 Engine - Displacement On Demand

Building the LT1's top end for 400-plus ponies

Step By Step

Minus a set of valve covers, this is Golen's complete 383 LT1 longblock, capable of over 400 horsepower and 450 foot-pounds of torque.

Ported to perfection, there is nothing stock about these LT1 cylinder heads. When combined with a lumpier cam, Golen expects an additional 20 hp from the base 400 hp LT1 package.

The bowl area is roughed-in using a carbide tip grinder and some WD-40. The next step is polishing--first with 320-grit sandpaper and then with medium grit Scotchbrite brushes. The same basic procedure is followed on the intake and exhaust ports to increase flow into and out of the combustion chambers.

On the intake ports it is especially important to reduce air turbulence and keep as tight a seal as possible to the intake manifold. For this reason the intake ports are gasket matched. The gasket is placed on each head and a bluing spray is used to mock up the edges of the gasket in relation to the intake ports. If you look closely you can see a line in the blue around the ports. Technician Dan Eddins will have to remove a chunk of aluminum that forms that sharp, square edge to make a smooth and rounded union with the gasket. The intake manifold will be ported to match the gaskets as well.

In part I of our crate LT1 build (March 2005), GMHTP described the process by which Golen Engine Service produces its affordable 383 LT1 short block. While the age-old adage "there is no replacement for displacement" remains true, it is also no secret that the heads are what make the power. After all, what good are larger cylinders if you can't fill them? In this particular engine build, the customer has opted for a custom ground camshaft and extensive porting to the stock LT1 heads to take full advantage of the extra displacement. The hope is that the combination will net an additional 20 horsepower from Golen's 383 package.

While some of Golen's customers opt for AFR cylinder heads with their superior flow characteristics, porting the stockers helps keep the project under budget. In our coverage of customer Val Becker's LT1 build, a great number of man-hours were spent enlarging the bowl area around the valves as well as the intake and exhaust ports. Manley stainless steel 2.00-inch intake and 1.55 exhaust valves were used to replace the 1.94/1.50 valves from the factory. To complement the porting of the heads and the addition of larger valves, stronger springs and bronze valve guides are also added. With the sturdier valvetrain and better flowing heads, this LT1 is sure to make good horsepower numbers in the upper rpm range while increasing reliability.

With Golen's street and strip packages, drivability is an obvious concern. In this case the cam selection, as discussed in part I, is not radical enough to make Val's Camaro any less streetable. The compression ratio can also make daily driving impractical, as too high a ratio will require expensive, high-octane race fuel. Owner Chad Golen says, "by keeping compression at 11 to 1, we manage to avoid having to pull out timing or risk detonation and the life of the engine while using 91 octane unleaded that you can get at just about any gas station in the country." Chad recommends using conventional motor oils with his LT1s, which also keeps cost down, rather than synthetic counterparts. GES uses Valvoline VR1 Racing oil in all of its engines, which he says is more than adequate for the iron block LT1s.

Prior to purchasing any of Golen's engines, Chad personally discusses all recommendations to his customers and makes any necessary changes to the packages. First the details of the application are reviewed, including whether or not the customer will be using power adders and how much power they are looking to make. Based on this information he then advises the client of which packages or options would best suit their needs, then inputs the final order into a custom designed computer program. "About 90 percent of my customers do order the packages right out of the book; however, the packages are not set in stone. For example, with this project the customer upgraded a number of parts in the rotating assembly, and added additional porting to the heads and a custom cam."

Perhaps the most attractive part of Golen's engines is that they come with a lifetime labor warranty. Chad is so confident in the build quality of his engines that should there ever be a mechanical failure he will rebuild the engine free of charge. With that type of guarantee, purchasing one of Golen's LT1s seems less like an expense and more like an investment. At least that is what you can tell the wife; meanwhile you can smile at the thought of 383 cubes and 400 horsepower under the hood.

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