LT1 Cylinder Head Comparison - LT1 Head Shootout!

We Test The Best Off-The-Shelf Lt1 Heads On The Market And The Results Are Quite Surprising

Justin Cesler Aug 1, 2009 0 Comment(s)
0908gmhtp_01_z Lt1_cylinder_head_comparison Project_motor 2/27

Picking a cylinder head for your latest project motor really is a tough, somewhat confusing situation. With prices ranging from hundreds to thousands of dollars, slick advertising talk skewing the facts, and little to no reliable independent testing, it is no surprise that people end up with some pretty wacky combinations.

With head technology constantly evolving and a fiercely competitive market always pushing development, it is time we sat down, built a nice short-block, and put them to the test. It is important to note that, while tempting to name a winner, each head in this particular test has its advantages and disadvantages. While peak horsepower is important, we recommend you also look at your specific goals, budget, and future modifications before picking a cylinder head. Much like life, it is important to figure out what is best for you and go from there.

The Test
For this test, we turned to our friends at Golen Engine Service in Hudson, NH, to help us build and dyno each combination. Based on what most people would build, we assembled a mild 383 LT1 capable of making good, streetable power on pump gas. With a target compression of 11:1 we had each head decked to 54-55 cc combustion chambers. Since this was going to be a street engine, Comp Cams sent us a very mild 280XFI camshaft, which features 230/236 degrees of duration, 0.576/0.570-inch lift with 1.6 ratio rocker arms on a lumpy 113 LSA. We felt that most of these heads would do quite well with this camshaft, and with a group average of 495.4 hp, we were quite impressed. All of the heads, except for the Edelbrock RPM Xtreme LT4, were tested using a hand-ported LT1 intake manifold. Chad Golen has perfected the art of the LT1 manifold and feels it offers a great upgrade to any performance LT1 build. The Edelbrock heads were tested using the excellent Air-Gap LT4 manifold, since they ship port-matched to the much larger raised-runner LT4 race port intake manifold gasket. To make all of this happen, you need a lot of gaskets and we thank Fel-Pro for coming through with five sets of head and intake manifold gaskets. Without these, we would never have been able to complete such a test. With the engine assembled and bolted to the dyno, we will let the heads do the rest of the talking.

All testing was done with 38 degrees of timing, 43.5 lbs of fuel pressure, Standard correction, and a consistent 12.5-13.0:1 air/fuel ratio. Had we chosen to adjust timing for the differences in each head, most likely we could have increased peak outputs, but would run the risk of human error. A variable we, instead, chose to keep constant.




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