Overview Reviews Product Description 558-302 Holley EFI Tach Input Ignition Adapter This is only used on applications using a CD Box, such as an MSD 6AL, while not using timing control. Product Videos Custom Field Product Reviews Write a Review Write a Review × 558-302 Holley EFI Tach Input Ignition Adapter Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Email * Review Subject * Comments *