If I were you I would get the lash straighten out first, and then move on from there. I was having similar issues, I was struggling to hit 9.5 @ 77mph in the 8th, and the culprit..... a broken pushrod due to too much lash. Well after pulling the intake (to remove pushrod) I put a new pushrod in and set the lash. Well that was fine and dandy untill 15 mins off driving it bent the new pushrod like a banana. The lash had collapsed a lifter. Moral of the story a little "valve tap" can cause major headaches. I would start there since you know it is a problem, and then start with the opti, o2's, plugs, wires etc. if it does not fix the issuse. Do not just throw part at it in hopes of fixing it. It is not cost effective or time effective (don't ask me how I know ) Any way good luck find the problem.

 

Its a 93, there is no KM in there, speed density as opposed to MAF in 94-up.

 

thanks for the replies I'll have to get working on it. BTW at least I beat the Mustang 5.0 on the second run

 

Something is most definetely wrong with this situation. 15.0s are mustang territory. my 94z went 14.08 @101 with my shi*** driving and a 2.2 60. Id say that a tune up, driving practice and a better track u should be running 13s. Good luck Those times were when my car was bone stock.