1) I wouldn't rev that high.a couple weeks ago i was driving my car. i havent driven it hard in a while so i figured what the hell. took off in first, everything was going fine till i hit right around 5k. at 5k there is this usually this loud hissing noise. sometimes there is a whoomp noise. and the car looses a ton of power at 5k and beyond. i can drive the car around all day long just fine, but the second i try to go to 5k or higher it just always makes this noise now. i think i blew the stock intake manifold gasket or i may have sucked something into the manifold(not likely without way worse things happening). any opinions or people that this has happened to?
2) The manifold gaskts are metal so I highly doubt you damaged one.
3) Check the OEM intake "scoop" ad verify that it is still fastened to the frame. could be getting sucked up against the hood causing the hiss noise and loss of power.
4) You need to provide many more details. Mileage of the engine? Mods? Check engine codes? Last time spark plugs were changed?