100hp @5600 (94lbft), 109lbft @3800 = 79hp
typical 2nd to 3rd gear change, 5800 to 3850, keeping around 80 to 100hp all the time
80hp / 1.2 tonnes = 67hp/tonne
100 / 1.2 = 83hp/tonne
75hp @4000 (98lbft), 144lbft @2200 = 60hp
typical gearchange 4200 to 2600, staying around 66 to 75hp
66 / 1.08 = 61hp/tonne
75 / 1.08 = 69hp/tonne
or in other words, your *peak* power in 2nd/3rd per weight would barely beat the "bottom end" of his 3rd gear if he was doing a reasonable high-revs racing change. by rights you should have got your arse kicked

so some other factors at work there.
with traction control, from a red light, and all other things considered, you'd probably have him on a standing start, maybe to near the top of 2nd if both cars had similar gearing.. but then you'd be left for dead.
lots of torque is good for low down grunt, punting about town and not having to change down so often, but in a race the advantage is lost due to the higher gearing a lower-revving diesel needs. speed-wise it's all about the end-result horsepower - torque multiplied by revs (or, divided by gearing).