Systemax - The stock Gen VI 502 is no slouch right out of the box, producing 450 hp at 5,250 rpm and 550 ft-lbs of torque at 3,500 rpm. This is a very streetable engine, and all of the bottom end parts are stout. Addition of the SysteMAX components (with EFI) turned up the wick by a full 105 ponies (to 555 hp at 5,600 rpm) and cranked up the grunt to 564 ft-lbs at 4,700 rpm. The beauty of the SysteMAX parts is that streetability was not affected. Idle was nice and rumpity at 850 rpm, but stable enough to produce good vacuum. Throttle response was very crisp, and there was no off-idle stumble.