Calculating heat of combustion via calorimetry
You have 60 g of $\ce{C60}$ (which has a molecular weight of 720.6), so that means you'll need to multiply your answer by 720.6/60 which (cleverly) turns out to be 12.01. Another way of saying it is that you have calculated the heat of combustion for 1/12.01 moles of $\ce{C60}$, so you'll need to multiply your answer by the inverse in order to get the desired (per mole) quantity.

Using your notation, numbers, and noting that a change in one degree Celsius is equivalent to a change in one kelvin:

$$\Delta E_{\rm molar} = -12.01\;\mathrm{mol} \cdot 300\;{\mathrm g} \cdot 4.18\;{\mathrm J} \cdot {\mathrm g}^{-1}\, \cdot {\mathrm K}^{-1}\, \cdot 10\;{\mathrm K} = -150.6054\;\mathrm{kJ}\cdot\mathrm{mol}^{-1}$$