help with time slip

well guys went out to tnt yest. and had a good time got to the track could not hook at all 60' was 1.893/1.880 set out for a little while and let the big boys good put some heat in the track and some rubber down...went back did a pro mod burn out to get some heat in this old tires and was happy with what happ. 1.689 60' leaveing at 2000 rpm at 7.575 et and 88.736 mph was good to go ..now I go back to run a freind with a 80some modal z28 with a 350 and 28 tall slick same burn out this time i leave at 1500 1.660 60' and 7.567et and a 88.663 mph worked pretty good push go pedal on him a few times at end of run...now heres my 2 best time slips so you guys give me some good info to try and do or change ...

rea. 110
1st. 1.673
2nd. 4.837
et. 7.549
mph. 89.476

36 total time
12psi tire
1500rpm



next pass rea. -.104
1st. 1.696
2nd. 4.855
et. 7.576
mph. 89.038


36
12
1500

i think it has more in it with a verta change and a tire change...i took a look at the tach at the end of the run and im turning 5000 when i cross the line....also plan to check my tach against a diff. one...i plan to try a 8 5000 to se if thats about where i need to be..i know its not going to be perfect but close i hope it was on a 340 before .....plan on 28/10 29/10 slicks i have 4.57 now what would the aff. be with a 4.88 and a 29/10 being that it turns 5000 at the end in the 1/8 th mile......thanks guys keep the mopar info comeing....:cheers: