swap 3.90's for 3.73's???

I dont know. It seems like there is a very small difference between 3.73's to 3.90's. Most people say that the difference between 3.73's and 4.10's isnt that big either, but obviously larger.

I know someone who is putting 4.10's in his blown GT, hes making a little less power than you are. Hes aiming to get the gears done by Mustang Week.

I used to think there was a small difference between 3.73 and 4.10 until I drove a car nearly exactly like mine with 4.10's and holy crap it was crazy. I felt like I didn't know how to drive lol.. Downshifting was the main difference I noticed tho

So having not driven in a re-geared car except for once, but it was a 5.0 LX, I will ask how big of the ass dyno factor comes in when switching from stock gears to 4.10's.

How much of a difference? I know someone going 4.30's in their auto GT, 4.10's in their blown 5 speed GT... People with 4v's going 4.30's and higher. Damn!!! I would like to be able to comfortable cruise down the interstate at like 70 without taching really high. I would also like to be able to rip balls off the line, which is a MAJOR flaw with stock gears. Trying to punch it from anything below 3500 RPMs feels like a waste of gas to me.