None... I had a 150 shot of NOS on the car but that 650hp was on a dyno naturally aspirated (no NOS).
Let me start from the bottom of the engine and work my way up.
Eagle Forged and Internally Balanced bottom end (Crank, Pistions, Rods). Fed Mogul bearings. I used the Impala head gasket to raise the compression ratio a little more. Had the block decked and the heads milled. ALso had the heads 5 angle jobbed, with oversized Mildon valves and a full Crane valvetrain (Double springs, hydro roller rockers, hyrdo roller lifts, hardened rods) with the Chevy LT4 HotCam. With Full length jet-hot coated headers (specially made for the Z-28's and Firebirds).
Drivetrain wise after blowing up two automatic (4L60E's) I converted over to the T-56 (6-speed manual) and was happy. But with the 3.73's I had in the rear of the stock rearend the rear finally gave out so I installed a fully independant Ford 9" rear with 4.11's (since I had the 6 speed I could run 4.11's on the street and still get 8-10mpg city).
Suspension wise I had full Granatelli. Adjustable lower A-Arms, sub-frame connectors with the X-brace,adjustable lower control arms with adjustable brackets to lower or raise the angle they were on for better traction under different circumstances, double adjustable pan-hard bar (keeps the rear end from shifting side to side), and 2" dro Eibach springs. 8 point internal roll cage with dual Ricarro front seats and Simpson 6 point harnessess (yes 6 point not the 5 point ones). An assortment of VDO guages for everything (even rear diff temp). The whole thing ran on 18X9.5 and 18X11 (rear) Corvette ZR-1 black rims (the real thin 5 spoke rims) with BFG Comp T/A ZR's 275/45/18 on front and 315/35/18 on rear. Had a 4" cowl hood, the 5" RS type spoiler (similiar to the late 70's Z-28's spoiler) 5% tint all around.
You might be like "yeah right"... but keep in mind that I raced it in the SCCA leagues for 3 years and had sponsors (TByrne Motorsports (he's a big supporter of F-Bodies, camaro's and firebirds), Simpson, BFG (actually Michelin who makes BFG's), and had Granatelli for a little (hence my full suspension from them).
Boy do I miss that car... I still regret gettin rid of it, she was SUCH a rush!
Later all.
-Chris