How slow will a rear end ratio make your car?

Nice i wishi i was lucky enough to have a girl that liked cars everytime i find one that does its scary "Whoa god, Im already seeing someone, bye!" Nowadays though everyone is into the imports. I can't wait to have my build done so i can rape the stis and evos that come my way.
 
Yeah it amazed me to find her.She had the car when I met her.She picked it out her self and pays for it on her own.Its a 2001 WS6 Firehawk,red with black anv. stripes .But the stang will be faster some day.
The vacum modulator is new. I replaced it about 3 months ago.Are they adjustable?
 
Some are adjustable, some aren't. You won't be able to adjust it to shift at 6000rpm though.

With those heads and stock manifolds, 6000 rpm won't be your power peak anyway.

As it is, you have too much cam for your combo. Get gears, get a decent stall converter, put a shift kit in your C-4, and get headers. Then you will make the power you want.