Any gearhead worth his quart of synthetic oil will tell you that the fuel level in a carburetor is a very important setting for maximizing the performance of a the engine and the car. The fuel level is a function of two main parameters the float setting and the fuel pressure. If the fuel level is too low it'll require a greater vacuum signal before the main venturis will start to deliver fuel, the result will be a hesitation or stumble as you come off the idle jets on to the main system, a leaning of the air fuel mixture and a power loss.... and to a gear head that's a very bad thing. Have the fuel level too high and fuel may spill out through the venturis due to fuel slosh. This will play havoc with the low rpm operation of the motor, it may even shoot out the air bleeds if there's any fuel boiling on heat soak, and it can even prevent engine starts by flooding if the car is parked on a steep hill. When Darrin built and tested the engine the carburetor was tuned to perfection and the engine would pull hard and smoothly from any RPM above idle. All was well on the road until he tried some very high G (>1) turning and braking maneuvers, under such conditions it would stumble and crackle out of the corners due to fuel spilling over (like a high fuel condition) and frequently cough and stall at the end of a very hard braking from high speed due to the same problem. This wouldn't occur in a vehicle of lesser performance but he'd engineered the chassis beyond the capability of the fuel system. He installed various baffle anti-slosh kits with little improvement and didn't want to lower the floats as the dyno had indicated a power reduction. Darrin thought it would be a sacrilege to switching to fuel injection as it was against the spirit of such a classic.... furthermore, he matched the carb to the intake and port matched the intake to the heads... and had done over a hundred hours of porting to get the maximum flow and power. He needed another black electronic fix it box to solve the problem... so this is what we engineered. This box fixes the above carburetor problems and it does so without restricting maximum power/fuel flow by making it act somewhat like a fuel injection system. We used a number of sensors to measure engine load, brake activation etc and used the information to control the fuel pressure accordingly such that under low engine load and braking the fuel pressure and hence fuel level was lowered, step on the gas and it was restored to the optimum level. Essentially the fuel pump was fed a 30Hz square wave instead of the constant battery power, the width of the peaks was controlled to modulate the fuel pump output from maximum when it got constant power down to an adjustable minimum. We installed the system then set the minimum fuel pressure at the lowest level that permitted smooth idle, we then took the car for a spin and adjusted the engine load points (starting from our guess-estimates) at which it would start to increase the fuel pressure from this minimum and the engine load point above which it would always be maximum (it adjusted linearly between these points). Net result problem solved and gas mileage increased a little too. Not bad when a performance solution also increases your mpg.