Marine City, MI… October 7, 2021 – Howell EFI, a leader in EFI conversion kits (GM/TPI/TBI) and wiring harnesses for direct injection swaps, now offers plug and play LT1/LT4 and EcoTec3 wiring harnesses for classic muscle cars, Corvettes and trucks. Howell now offers multiple options to transplant power for both automatic and manual transmissions and even supercharged classics. The LT1/LT4, and EcoTec3…