How do PSI, Current Performance, and BP Automotive conversion harnesses compare?

Here is what the documentation says. Each point links to its source; details depend on your exact computer, harness and transmission.

• Howell standalone harness: Howell standalone harness: Bosch relays, fuse block, OBDII port, built-in CEL. (LSX Magazine)
• Howell LS-1 standalone harness: Howell LS-1 harness grounds at the back of the LH head; CARB version keeps emissions. (MOTOR)
• Sources differ: Standard-form standalone harnesses (PSI, Aeroflow, BP) delete EGR, AIR, CCP and rear O2s; the CARB direct-replacement Howell retains all emissions functions.

Confirm against the instructions for your exact parts before wiring. More: Harness and power in our tuning guide.