Hi I'd like to get 4.10 gears. I have heard some great things about them so i decided to buy a set, but got questions:

1) will i need the installation kit with the gaskets and everything and oil my car has only 24000

2) what are the best gears to get, Ford racing, richmond, etc

3) will 4.10 be a good idea, I am only into weekend racing

4) what would be my top speed limit

5) do i need to reconfigure my speedometer, and how do i have to buy a kit or something?

6) every thing you think i should know when changing gears

regards

First of all, I wouldn't say this is a 'do-it-yourself' job. It's a little more complicated than 'unbolt and bolt'. I would take it to a replicable speed shop or a dealer.  They will know what to replace and what not to replace(yes, they will replace the gaskets,seals,rear-end fluid,etc.) Depending on what year your car is depends on the gear you should use. For the 4.6L I'd go with 4.10's if I raced alot,3.73's just on the weekend, or if you do alot of driving, the 3.55's are a good choice. For the 5.0L go w/3.73's primarly for racing, are 3.55's for weekend racing.  If your car is a '99-up, you will have to have your speedo recalibrated.  For the earlier cars, all you'll need is a $15 speedo gear that is located at the end of your speedo cable in the trans.   

I knew I'd forget something.  I'm sure Richmond gears are good quality, but I've always used FMS gears w/ good luck. Top speed all depends on your wheel/tire size and rpm limit.  On a '87-'93 w/ 16" wheels, 245/50 tires, 3.55's and in 4th gear, your 'stang will be at about 130mph @6k rpm's.  Knock about 8-10mph off for each lower ratio,or add the same for each higher ratio. However, you can actually top out in 5th, but it's a slow gear change (can't really speed shift) and there is a big drop-off(from 4th to 5th).  

Thanks 7seven for your reply and even though I've been doing all my mods they are just mild mods so in this case definitively I am taking it to an auto soport shop the only thing you got me thinking is my decision between  3.73 and 4.10's cause i'd like to have a huge acceleration but don´t know how my car is going to react on a daily rush hour on the streets