Apples:
116 mph sounds very good. But be carefull, G-tech are known to be imprecise. Personally, I recommend and use AP22 from
www.race-technology.com, it is more consistent and gives you more information.
By the way if you want to convert your MPH into HP use following formula:
HP = ((MPH x 0.00426)*3) x Weight
so in your case 116 x 0.00426 = 0.4942, cubed it is 0.121 times 4200, your HP is 507 at the flywheel.
Judging from your dyno of 408HP at the wheels, your flywheel HP at 15% loss should be 480HP.
Pretty close.