My buddy got back to me with some details - in the carbureted configuration everyone used to run a normal diaphragm style pump mounted in the usual spot and driven by the eccentric on the camshaft. They moved to Waterman pumps in the back of the car a few years ago driven by cable, and the cable drive was generally built into the bell housing and driven off the back of the camshaft (like Hworrell said). The engine fired on start using fuel in the carb bowls - not so easy with injection as you would have to spin the engine for a while to build pressure. The McClaren ECU is based on their design from the IRL where they spin engines at about 2500 rpm with a 5 horse remote starter, which is not the NASCAR way where the car has to start on it's own. This caused a lot of discussion with the tech guys at NASCAR about how the fuel supply would change.

They initially were pushing for cable drive only, but testing earlier this year showed starvation problems down the straights so they moved to electric drive main pumps. Current fuel system guidelines require a "reservoir tank" not more than 100 ci internal to the fuel cell, and the main (pressure) fuel pump is either mounted internal to that tank or takes suction from the bottom of that small tank, which is limited to 10psi internal pressure. Most everyone uses a cable driven pump to scavenge the cell and move the fuel to the make up tank inside the cell. The electric pressure pump is located in the make up tank but can be external. Pump controls are stand alone, not in the ECU. The big thing is this could all change ten more times before Daytona