The easiest way to distinguish the factory M8A/B vs the Elva M8C is the bottom of the sidepods. The factory cars were square while the Customer cars had a rounded or curved bottom edge. I don't know of any particular reason other than fuel bladders were located there (one season they even had a 3rd tank under the driver's knees. These were real men back then) The squared off side pod possibly allowed another extra bit of fuel. The curved bottom would restrict the total fuel capacity and thus force the privateers to ever so slightly detune the engines so their fuel would last for 2hrs. ONE of the M8C's glaring weaknesses was the lack of fresh air reaching the driver. Almost all the Can-Am cars got incredibly hot. John Surtees drove an M8c for several rounds and had a flexible tube, similar to the brake duct tubes, strapped on top of the nose and run around the windscreen to provide 'some' cooling.