effect of rearend gearing on ET's

okay well i have the correct gear ratios for the tranny entered, stock duster weight (they let you pick vehicle- only abody there it says 3410lbs), and the rollout is set at 0 ( i dont know if it should be altered?)...my scamp isnt actually driveable yet, but im screwing around with the program to just get an idea how my combination will fare...and yes cracked back my 60 ft time is about 2.7...however, how does that explain my high mph? I tried slowing the launch speed down to about 1500rpm and it only made me a couple of tenths slower and dropped my 60 foot to about 2.5...there is something about a traction coefficient which is right now 1.68...what should it be?