3:73's or 4:10's
 

Hi I have a 91 GT 5.0 and it's a aod w/ TCI street fighter tranny I have a brazed converter, 190lph fuel pump, fuel pressure reg, pulleys, american thunder cat-back, mac headers, then a bunch of suspension parts anyways should I go with 3:73's or 4:10's I'm a senior in high school and hit up the track whenever I get the chance but not every weekend. What would my rpm's be at with 4:10's going 60 or 70mph. What kind of et time would I see with 4:10's then 3:73's. Thank you

we would need to know your tire size before we could tell you rpms. There is a link on the left that says analyzer. That should tell you what you want to know.

Gear ratio & RPM's
 

Generally, a 5.0 Mustang with the AOD benefits the most from 4.10's.

5-speeds usually do best with 3.73's.

You'll see around 2400 - 2500 RPM @ 70 mph in high gear (ballpark number).