Need Advice??

[WildBill]

Programer is almost a must have item. As a DD 4:10's maybe a little steep, but the 20 " rims will bring it down a little bit. It depends on what you can live with as far as rpm goes, especially on the highway. What rpm are you turning right now at 70 mph? 2000 +/- a few? I have 3:55's and at 70mph I turn almost 2300rpm with 18" wheels.
There are calculators on the web where you can plug in your info ( trans ratio, rear end gears ....ect) to get the rpm at any given speed. Play with one of those and see what you can live with.
Remember the higher the constant rpm the more wear and tear your drive train gets and you mpg go to shi*t fast.
my 2.5 cents

Fuel mileage on the highway doesn't really go down much at all, if any. CITY fuel mileage will actually INCREASE since you can get into top gear and cruise easier without opening the throttle as much.

[TorchedMach1]

Fuel mileage on the highway doesn't really go down much at all, if any. CITY fuel mileage will actually INCREASE since you can get into top gear and cruise easier without opening the throttle as much.

Yeah what he said. Heck with it go 4.30's already.

[WildBill]

Yeah what he said. Heck with it go 4.30's already.

If it was a 4V, I say hell yeah!
4.10s are the perfect gear for him.

[F&S Stangs]

Wild Bill, it's a 3V....so 4:10's are not good?
Also you mean to tell me that two identical mustangs 4.6 3V 5 spd cars driving on the highway at let say 75mph one turning 2000rpm and the other one turning 2600rpm, that they would get the same or almost the same mpg.......

[WildBill]

Wild Bill, it's a 3V....so 4:10's are not good?
Also you mean to tell me that two identical mustangs 4.6 3V 5 spd cars driving on the highway at let say 75mph one turning 2000rpm and the other one turning 2600rpm, that they would get the same or almost the same mpg.......

Yes Sir. I know it's a 3V. LOL............He's NOT gonna be turning some outrageous rpms. He'll be fine with 4.10
I wouldn't tell him so if I wasn't sure. You'd be amazed at what these cars will do with the 3v and cam phasing.

[GT Larry]

My 2006 has the 5 spd and just had 4.10s installed by A1 differential. Wow!! they really woke up the ride, more than the cold air and programming. 5 speeds go with 4.10s, I havent noticed any excessive RPM issue with them---should have done it sooner.

[Jodaddy]

its been woken from the dead!! Ive had my gears for almost a year now lol couldnt be happier!

[BigSkyLLC]

Can't really give you advice but my opinion is that 4:10's are fun around town but personally would drive me nuts on the highway.