has anyone installed or used a 390 gear ratio w/ 5speed trans setup? If so how streetable? and what kind of mi did u avg? Also has anyone gone higher than 410s?
i belive they come stock with 3.31's at least mine did. so i would think 3.90's are pretty streetable. in my 88 LX, i went from stock 2.73 to 3.73 and it was a real big difference. from what i remember they sayd 3.90's are for the guys who arent sure for 3.73 or 4.10's
I've been running with 4.10 for quite a while now and would recommend it to anyone. 3.90s would definantly be steetable. At 80mph I run at 3000 rpm and my top speed is about 140. With the way I drive VERY aggressively I manage 17mpg. I stayed off the throttle for a week and reset the meter and got 20mpg. Personally I feel this is adequate for a daily driver. There are a couple cats on here running 4.30 and I'm thinking I should have prolly been one of them but its not worth taking the gears back out.
Make sure you will be happy with the gears you get cause its WAY too pricey an install to be unsatisfied.
3.73 are ok from what I've heard
4.10 have made a really decent improvement on my car and would recommend
4.30 are for weekend warriors or hard-core enthusiasts
4.56 are WAY too much for the street
i would also recommend 4:10s, if you do any highway driving at all, imo anything higher would be too much. like galaxie said at 80mph on highway you are right around 3000rpm. gas milage w/ a good tune i avg about 20mpg. if this is not your daily car and you like the track go for 4:30s+. also im pretty sure a stock 05gt w/ manual tranny came w/ 3:55s. so i would definitely skip at least one gear altogether to get your moneys worth.
4.10's definitely. Besides, I don't think FRPP sells 3.90's. You'll end up with Motive more than likely, and also, more than likely, you'll have gear whine. Don't fear the gear. 4.10's are more than streetable.
Not enough difference between the 2. Get the FRPP 4.10s and you won't be unhappy at all. Even in my 5 speed auto I can still snail out some 24 MPG tanks with the 4.10s. I keep a log of my mileage and before any of my mods EXCEPT for the Flows I averaged 20.52 MPG over 10K miles. The 7K miles since then I have averaged 19.50 MPG.