I just read at a vette forum that the '85 could do 14.3 @ 97 mph right from the dealership. With very minor tweaks it would get into the 13's.......so that's pretty good for a luxury car.
Gearing is the single best thing that you can do to any hotrod. With the over drive 5 speed trannies, running a 4:11 or 4:56 rear is no big deal now. Plus these new trannies come with 3:1 first gear, so your launch can be done at 12:1 or better. The 85 vette has plenty of room for wide sticky meats, so there really isn't much need to do much with the engine except tune it for 6000 - 6500 rpm shifts.
I've priced the 5 speed OD swap for my Ford and it would be about $4000 with the TKO 500 trans and all the other components to convert from an automatic trans.. The standard "World Class 5 speed is only rated for 300 Ft Lbs and I haven't seen any 400 Ft Lb options