Mate,was only going by the 400hp info provided by the OP and comparing it to mine.
Mine has 400hp and I've turned 7.6@90 in the 1/8.
Most cars don't work as well as mine so that's why I gave the 84mph number which should be good for around an 8.1.
If your 8.4 prediction is more correct then that would only be around 80-82mph in the 1/8 assuming he can get bite.
At the end of the day it's all just numbers and none of us are necessarily wrong:thumbup: