Gauge panel for test stand I built. Pull switches for Ignition and fuel pump, push button for starter. mechanical water, oil gauge, vacuum gauge for tuning, tack for rpm. Fans are from a wrecked school bus under-bus A/C condenser. It takes all four to keep a new engine cool running at 2500 rpm for 30 minutes. I have since turned the radiator around so the air from the fan hits the engine, they used to blow out away from it. The air across the headers helps cool the whole thing down. I always have a water hose close by for added cooling if needed. Once the engine starts, I do everything I can to keep them running, tune on the fly. Once the break-in is done, I can slow it down and set the adjustments.
The fans run right off the battery with 8 gauge power and ground, two fans per switch. With all four running you can hear the engine slow down from the drag on the alternator.
