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Crate LT1 Engine - Displacement On Demand

Building the LT1's top end for 400-plus ponies
By Scott Parker
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Minus a set of valve covers,... 
   
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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.
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Ported to perfection, there... 
   
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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.
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The bowl area is roughed-in... 
   
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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.
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On the intake ports it is... 
   
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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.
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The above picture is the unported... 
   
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The above picture is the unported combustion chamber...
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...when compared to its reworked... 
   
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...when compared to its reworked counterpart it is apparent not only how much material has been removed, but also how much smoother the finished product looks.
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The valve guides are drilled... 
   
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The valve guides are drilled to allow room for the bronze liners on the Serdi 2.0 valve seat machine by machinist George Connoly. This restores the proper clearances as well as adds the benefits of better lubricity, scuff resistance and wear. The liners were provided by Golen's neighbors New England Competition Engines, and are the same as those found on their tricked-out circle track engines.
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Next the bronze liners are... 
   
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Next the bronze liners are drilled into place.
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A carbide ball is used to... 
   
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A carbide ball is used to size the valve guides, which require two thousandths of clearance on the exhaust size to account for heat expansion and only one thousandth on the intake.
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The valve seats are then ground... 
   
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The valve seats are then ground down using the Serdi to fit the new 2.00 and 1.55-inch valves.
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After the valves are back... 
   
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After the valves are back cut, the three-angle valves are inserted.
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The valves are lapped to ensure... 
   
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The valves are lapped to ensure that they are seated properly. Exhaust valves should meet the seat in the middle third of the face for street cars, so that they do not get burned up.
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The intake on both street... 
   
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The intake on both street and race cars can be fairly close to the edge as heat is not a factor.
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The pointer is used to line... 
   
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The pointer is used to line up the edge of the cutter with the valve to ensure the proper angle.
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The heads are vacuum tested... 
   
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The heads are vacuum tested to makes sure each one of the valves is sealing properly. Seven BAR indicates proper sealing.
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Using pipe cleaners and cleaning... 
   
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Using pipe cleaners and cleaning solvent, burrs and excess material are removed from the valve guides. Then the valves are placed in each one of the guides and moved up and down to make sure everything moves smoothly without resistance.

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