I had pretty much the same
stang and went to 3.73's and it was like nite and day difference. felt like i gained 50rwhp, though i really didn't. Later went to 3.55's and i didn't like it. went to 4.10's later on and it was awesome.
Are those gears used? i would be very cautious about used gears. If you look up speedo gears, you'll find the right color to get. with a 95, you most likely will need a bearing kit, 3 bottles of royal purple gear oil and google some instructions on it. It's not the easiest if you've never done it before.