Overview Reviews Product Description 17-91 Holley EFI Billet 4500 Injector Spacer W/EFI Rails This CNC machined billet spacer is designed to provide additional fueling solutions for those using 4500 flange throttle bodies. It is also perfect for those seeking to chill their supercharged fuel injected combinations. Product Videos Custom Field Product Reviews Write a Review Write a Review × 17-91 Holley EFI Billet 4500 Injector Spacer W/EFI Rails Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Email * Review Subject * Comments *