It's not just the engine and trans though. You gotta address the suspension, the brakes, the axles, the rear diff, the tires, Oh lordy lordy. It goes deep. really really deep. Now if it's only for a dyno queen, ego stroking, brag factor build, then sure that stuff doesn't matter as much.
Here's my price estimate to get 1k whp to the ground and drivable.
Engine: 5000 in parts and machine work.
Trans: 3000 in build/parts
Tcase/driveline: 1000 in axles, tcase, diff, axles
suspension(neg) 1200 coilovers
Restoring GVR4 500 in bushings, arms, paint, new bolts, tie rods, worn out parts, etc (might be low)
Brakes 800 for brakes that will PROPERLY stop a car with that power
Tires 1200 pending on how many sets before a good set is found
front mount 600 ETS kit, hopefully big enough
Fuel system 1000 Solid pump, will be huge, I'm sure it's a low estimate since injectors will be 500-800.
Ignition system 400 New stuff should work, but 20 old parts will fail
Cooling System 500 Big radiator, silicone hoses,
Turbo/manifold 2400 Big ol turbo and custom manifold.
Tuning said beast 1000 Takes hours, not minutes of an experienced tuner's time. Good tuner=big money, Cheap tuner=big money to rebuild blown engine
hmm lets see 18600 so far just bench building. I could be off, but I think I'm close. Worst part is that any build will have little things pop up and everyone knows that that adds up.
Sure you could bare bones the car, do nothing but ebay crap or shortcut things, but then your in a death trap, risking your life and others. Also what's the point of making 1k hp in a car that looks bad. Even a dyno queen will cost well into the thousands of dollars.
