The Edelbrock part # 35873 Pro-Flo 4 XT Sequential Port EFI System for Big-Block Chevy Rectangle Port engines has the latest in technology and features. The EFI system comes complete with a black finish Pro-Flo XT intake manifold and 35 Lb/Hr injectors capable of 550 HP with 58 p.s.i. fuel pressure. Also included is a plug and play single connection distributor designed to work specifically with Pro-Flo 4 and a made in the USA fully terminated high-quality harness with clearly labeled connections for a hassle-free installation. The new Pro-Flo 4 EFI systems feature an all-new ECU with a faster processor; a water proof design and is half the depth of the previous ECU. It also has an upgraded Bluetooth chip that is faster; more reliable and will not drop connection. We ve added more features for the advanced tuner giving you control over air-fuel ratios; ignition curve; idle speed; acceleration fuel; coolant fans; Rev limiter while retaining the simplicity Pro-Flo is known for. The key to the system is our exclusive E-Tuner 4 app with dyno developed base calibrations. The E-Tuner 4 app uses a Bluetooth wireless connection to communicate with the ECU s self-learning capability to continually adjust the calibration to get maximum performance. E-Tuner 4 features a simple and easy to use setup wizard to help you get started. Best of all; the E-Tuner 4 app is free and can be downloaded from the Google Play Store; allowing you to use an Android based smart phone or tablet. If you don t have a compatible device; then we also offer kits that include a 7in. Android tablet with the E-Tuner 4 app pre-installed. Multiple dash displays are included to allow you to monitor engine vitals from an Android smart phone or tablet. Pro-Flo 4 does not require laptop tuning.