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The Edelbrock LS1 heads were designed with assistance from the engineers at Lingenfelter Performance Engineering. These heads possess only the finest materials, including COMP Cams 918 valvesprings and titanium retainers, yet are surprisingly affordable at $2,300. (The bare-casting Pro Port heads are available for DIY'ers for $1,279.) The heads have been CNC-ported to enable 300.5-cfm intake and 216.9 exhaust flow according to LPE. |
The combustion chambers, while CNC-ported, are kept at 65cc to maintain stock compression. However, notice the silky smooth bowl work that is sure to increase combustion efficiency. Stainless steel 2.02 intake and 1.57 exhaust valves will also help expel and replenish the cylinders. |
Despite Edelbrock's long-standing reputation, it seems late-model EFI lovers dismiss the company as an older-generation manufacturer. However, lately Edelbrock has been working very hard to shatter those perceptions by making some top-notch EFI performance parts. Its latest endeavor involved the design and manufacture of a high-flowing LS1 cylinder head. Edelbrock enlisted the help of Lingenfelter Performance Engineering, one of the best names in late-model GMs, to create this head, and you can bet we jumped at the chance to test it.
Having just worked with the fellas at East Side Performance on the Edelbrock nitrous install, I decided to head on back to Wallingford, Conn., for another story. This time we would use Robert "The Chef" Weber's 2001 Trans Am as the test dummy. Since its purchase, the TA has had three different cams and a few different exhaust setups. However, it was currently sporting the stock cam, rockers, headers, exhaust manifolds, and Y-pipe. Only an MTI airlid, K&N air filter, MagnaFlow exhaust, and a few free mods separate The Chef's TA from a completely stock LS1. With the help of the Edelbrock heads and a few other choice goodies, we hoped to take this six-speed F-body from 12.9s to solid 11s naturally aspirated.
The Edelbrock LS1 heads feature a 65cc combustion chamber to maintain stock compression. However, there is enough deck material to cut the heads up to .050 inch. High-performance, stainless steel 2.02 intake and 1.57 exhaust valves optimize flow from the CNC-ported 202cc intake and 83cc exhaust runners. Near-stock runners are optimal for stock-displacement LS1s like Robert's. According to Edelbrock, these heads flow 300.5 cfm at .600-inch lift on the intake side, and exhaust flow maxes out at 216.9 cfm. These measurements were taken on Lingenfelter's Super Flow 600 flow bench with 28 inches of water and a 3.90-inch bore. While I am sure the heads were tested as accurately as possible, we wanted to see for ourselves how well they flowed. So we headed over to Kehl Tech Performance, who has been crucial in putting together and holding together ESP's LS1s, and conducted our own test.
For the next phase of the cylinder head test we installed and dyno-tested the heads (with no other modifications) after baselining The Chef's TA on ESP's Dynojet. Once that was out of the way, we saw how much more power we could get from the heads by optimizing flow with Edelbrock's stepped 1.75-inch-long tube race headers, an off-road Y-pipe, and a streetable cam. ESP owner Ken Quartuccio applied a custom tune to dial in the new setup and optimize the increased efficiency with LS1Edit. Time to put Edelbrock's heads to the test!
The intake runners also have the telltale marks of CNC-porting; however, they are also kept near stock at 202cc for smaller-displacement motors. Similarly, the exhaust ports are also kept small at 83cc. | 
Ralph Kehlenbach of Kehl Tech Performance strapped the Edelbrock heads down to its Super Flow 300, which utilizes a slightly larger 4.00-inch bore and 1 7/8 exhaust pipe. When tested at 65 degrees with a wacky 29.95 barometric pressure due to an oncoming blizzard, the heads flowed 300.1 cfm on the intake and 210.3 on the exhaust at .600-inch lift. Ralph said the difference between Kehl Tech's numbers and Edelbrock's claims can easily be attributed to a difference in atmospheric conditions, or perhaps even the slightly different testing procedures. | 
East Side Technician Alfred Lassen began disassembling our test car's top end by draining the radiator, unplugging the plug wires, and removing the coil packs with a 10mm socket before starting on the intake tract and air pump. |
The fuel line to the fuel rail is unhooked and the wiring harness is unplugged before the 8mm bolts on the intake manifold can come off. Only a few vacuum lines must be unhooked before the whole unit can be liberated from the TA. The lifter valley cover is then vacuumed out, and the air pump diaphragm is tucked out of the way. | 
The 17mm bolts on the exhaust manifolds are removed, and the passenger side manifold comes out from the top, while the driver side requires a little maneuvering before removal from underneath. | 
There are 15mm bolts on the power steering pump mounted on the driver-side cylinder head, and once it is removed the tensioner is loosened and the serpentine belt comes off. The owner also had an AMW catch can (to help stop oil consumption) mounted on the passenger-side cylinder head, which also had to come off. |