At 6 1/4" your front end would sit too low. You would have to jack more height in just to meet legal minimum ride height.
Your engine would sit higher in the chassis, assuming the mounts are placed in the legal tolerences relative to the frame rails.
Make a model out of popsicle sticks, or just a rough diagram on paper, to see what I am saying.
Zeeing the front and rear clips lower the center of the car (main frame rails).
Keeping the car low works equally well for road racing or ovals on pavement. On dirt, a slight incresase in ride height promotes better weight transfer and keeps those low parts (pan, frame rails, etc...) from getting damaged. Remember that the dirt track cars have ruts to deal with.
My random thinking
Steve