EFI Performance LLC is a late-model GM, Ford, and Chrysler dyno tuning and performance automotive specialty shop.

February, 2017 - We have added a line of pigtails and adapter harnesses to products; check them out!

May, 2016 - Mail Order Tuning has been moved over here from TunedbyFrost.com but can be purchased through either site. We hope to have our product listing updated within the next few weeks. Thanks for reading.

92 - 94 LT1 Un-vented Optispark harness 95 - 97 LT1 Vented Optispark harness LS1 3 wire MAF to LS3/LS7 5 wire MAF Harness with IAT plug