Taking my 99 FRC to the track for the first time on thursday.. Ill be on street tires... the mods are as following...

Vararam Intake
LS6 Intake manifold
Ported Z06 Oil pump
New Water Pump
232/234 Comp Cam
Valvesprings
Timing Chain
March Underdrive crank pulley and belt
MSD plug wires
LG Longtube headers
Highflow cats
Corsa Indy exhaust with tigershark tips

I was told the car made 400hp, is that believable? How should I launch the car and what should it run?

 

I would guess that with good sticky tires and a good launch the car should run 11.60-11.80s. But, the street tires are more than likely put your 60ft time way higher than it needs to be.

As far as the launch goes, you will just have to experiment with it to find out. Really depends on your driving abilities and the condition of the track prep. I would say to try to controll the clutch release and not just dump the clutch. Try to have the clutch fully released in the first 10 ft or so of the launch, and start adding additional throttle as you feel the car starting to bite. It takes some practice and coordination of the two feet. Shift at your max rpms as quickly as possible.

I will make a stab at a guess and say first time out if you get a decent launch around 1.90 60ft---Oh I dont know, maybe 12.20ish @ 116-118mph Good Luck and let us know the results.

Just for comparison sakes, when I had my 99 FRC last year with only LS6 intake, ported TB, ZO6 Titanium exhaust, Vararam, and 275-40-17 Nitto DRs I ran a best of 12.33 @ 113.55 mph w/1.81 60ft. Last weekend with my 2002 ZO6 only mod Haltech CAI and the same Nitto DRs I ran 12.06 @ 114.94 mph w/1.797 60ft.

Sure would be nice if you could borrow some drag radials to launch the car on.

 

Not sure what tires you will be running, but here is a cut and paste for my launch on F1 SCs.
As for my technique, I generally follow Ranger with some subtle differences. (You can do a search on his excellent tutorial.) Tire pressure was between 24 and 27 psi. I always did a large burnout in 2nd gear to really heat up the tires. My launch rpm was generally between 3200 and 3600. The clutch release was relatively quick but not a dump usually within the first 10' of travel. I would begin to squeeze the throttle near the top of the clutch release and put it to the floor quickly but without stomping it. (All of the these items were directly related to the track prep.) I never power shifted but would fully or at least lift 3/4 on the 1-2, lift 1/2 on the 2-3, and 1/4 lift on the 3-4 provided that the track could take aggressive shifting. If everything is right, mid 1.7x is possible and 1.8x is expected.
Good luck. Let us know how you make out.