Holley Sniper 2 EFI Fuel Injection Kit - Silver 550-510-3XX 140-13379 This tells the ECU which

This tells the ECU which cylinder is cylinder #1 (or the first cylinder in the firing order as entered in the software)

Works with most popular boxed towels measuring 9-1/2" x 9-1/2"

x 4 3/8 in

If you are unsure

2007-2009 Chevrolet Silverado 1500 78

Holley Sniper 2 EFI Fuel Injection Kit - Silver 550-510-3XX 140-13379 This tells the ECU whichHolley Sniper 2 EFI Fuel Injection Kit Silver Product Description: Fuel Injection Sniper 2 EFI Throttle Body Square Bore Aluminum Silver The Sniper line of products are bringing high quality products into everyone's price range! Sniper is a one stop shop for a complete fuel system overhaul, including fabricated intake manifolds, high performance plumbing parts, fuel pumps & regulators, and a self tuning TBI style fuel injection system that starts at