Step By Step
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!