i'm fearing the gear......reassurance needed

fiveoho

15 Year Member
Apr 28, 2005
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TN
here in a few weeks im going to go ahead and have my 3.90 gear put in. the idea behind going from my 3.55 to a 3.90 is because of my combo ( see sig ). my combo should make pretty good power i think but im aware my heads are a little big along with my cam. my intake may not be the best choice but i got it because of price ( got a deal ) and because ive heard it makes good bottem-end. i figure the cars going to need a little more grunt out of the hole to compensate for the bigger heads and cam, hence the 3.90 gear.

it may be a few months before i get the combo in my car...maybe longer.
im thinking that gear will really help with that combo....right?

also, how do you guys think i will like the gear with the stock setup now? surely i will be able to tell a difference. im thinking it will be a little more fun to drive?

thanks
 
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I'm sure a lot of guys will say you'll love it but I'm one of those guys who doesn't like to give up daily driver even though I spend some time at the track. I went from 2.73's to 3.55's and I am glad I didn't go further. I don't want to be spinning the extra r's on the highway because of mileage and such. Frankly with mid 300 soon to be 400 horse the pictures people have taken it looks like I'm close to starting to carry the front tires on launch anyway. My thoughts have always been to look at where you will be going with the car and picking your gears, heads, etc. based on your final vision otherwise you'll be tearing into the car and your walet all the time as you slowly upgrade. That's just my opinion for what it's worth.
 
If youve got some good rear suspension/tires/driving skills, they will definitely help you get some good 60's. THe only "problem" I think you'll have is going through tires. Have you considered doing the gear after you do the engine mods, just to see if it works???
 
Dont fear the gear 4.10's daily driver~all day~everyday. Ive had them in the car for over 2 years now. If I was looking for some economy I'd sell the stang and buy a honda econobox. 3.90's sounds like a good gear all around.
 
Tonys89GT said:
If youve got some good rear suspension/tires/driving skills, they will definitely help you get some good 60's. THe only "problem" I think you'll have is going through tires. Have you considered doing the gear after you do the engine mods, just to see if it works???


yes, that was the original plan was to do it after the H/C/I. what it amounts to is, my mechanic has too much goin on and not enough time so whenever the rare opportunity comes up to get something done, ive been jumping on it.

will the tires spin alot more with that gear? im figuring they will some. maybe its going to be more noticeable than im thinking...
 
brothergoat5 said:
Dont fear the gear 4.10's daily driver~all day~everyday. Ive had them in the car for over 2 years now. If I was looking for some economy I'd sell the stang and buy a honda econobox. 3.90's sounds like a good gear all around.


thats my thinking too


i actually do have a honda for my DD :D
 
i think the rpm and milage problems with gears are way OVEREXAGERATED.

sure the rpms are up at highway speeds. sure it does hurt mpg a bit, but cmon were driving a mustang, if you worried about mileage, go get a hybrid car or something.

and its really not that bad, I have 3.90s and z spec t5 and in 5th gear at 65mph i only turn 2000 rpms even.

and yes tires dont last near as long.

i went from 2.73 to 3.90 and its a BIG difference, i am sure it will be plenty noticeable from 3.55
 
Foxfan88 said:
i think the rpm and milage problems with gears are way OVEREXAGERATED.

sure the rpms are up at highway speeds. sure it does hurt mpg a bit, but cmon were driving a mustang, if you worried about mileage, go get a hybrid car or something.

and its really not that bad, I have 3.90s and z spec t5 and in 5th gear at 65mph i only turn 2000 rpms even.

and yes tires dont last near as long.

i went from 2.73 to 3.90 and its a BIG difference, i am sure it will be plenty noticeable from 3.55


i agree. and i also believe its a bit exaggerated. sure, like you said, some things will suffer but not terribly bad.

you pretty happy with your choice on the 3.90s?
 
Foxfan88 said:
i think the rpm and milage problems with gears are way OVEREXAGERATED.

sure the rpms are up at highway speeds. sure it does hurt mpg a bit, but cmon were driving a mustang, if you worried about mileage, go get a hybrid car or something.

and its really not that bad, I have 3.90s and z spec t5 and in 5th gear at 65mph i only turn 2000 rpms even.

and yes tires dont last near as long.

i went from 2.73 to 3.90 and its a BIG difference, i am sure it will be plenty noticeable from 3.55


I completly agree :nice:

Some people just need to take the tampon out of their pus sy and stop being a girl! (This is a general statement directed at no one in this thread)

I swapped from 373's to 430's in my street car. The difference around town driving wasn't huge. The highway rpm's are fine. The car has seen a lot of highway since the gear swap. It rev's between 2300 and 2700 depending how fast I go.

A 355 to 390 swap won't be a big difference. You'll rev like 200 more rpm's on the highway. But more importantly you'll cross the traps at a better rpm.
 
fiveoho said:
i agree. and i also believe its a bit exaggerated. sure, like you said, some things will suffer but not terribly bad.

you pretty happy with your choice on the 3.90s?

i like em great! at the time of my gear swap i had the AOD still in b4 i did my t5 swap. i was going to get 4.10s like everyone said with the AOD.

my stock rearend was in crappy shape. carrier was worn so i suffered from 1 wheel peels, axle was bent. So instead of working on the POS i ran across a deal for a good price. I bought a whole 8.8 that was rebuilt with 3.90 gears, ready to bolt on for 400$

the difference was amazing, gave my old gutless AOD some... guts lol then when the t5 swap was completed OMG, words couldnt describe it. the old AOD was holding back the gears. 1st was tirespin, could get sideways in 2nd loads of fun.


my friend has 373s and really u cant tell much of a difference SOTP wise. but mine hits the traps right at 5200 rpm, right where a stock 5.0 peaks HP at.

might not be a big big difference feel wise, but the track will pick up the difference. maybe 2tenths or something. you will get off the line harder, and use all gears going down the track.

3.90 seems to be an oddball ratio, but lately it seems more popular than when i had first got mine.
 
Grn92LX said:
I completly agree :nice:

Some people just need to take the tampon out of their pus sy and stop being a girl! (This is a general statement directed at no one in this thread)

I swapped from 373's to 430's in my street car. The difference around town driving wasn't huge. The highway rpm's are fine. The car has seen a lot of highway since the gear swap. It rev's between 2300 and 2700 depending how fast I go.

A 355 to 390 swap won't be a big difference. You'll rev like 200 more rpm's on the highway. But more importantly you'll cross the traps at a better rpm.


sounds like the streetability is still gonna be just fine with the gear swap. if you rev 2300-2700 highway, i should be in real good shape then ( not that 2300-2700 is bad ). im anxious to see a difference
 
Foxfan88 said:
i like em great! at the time of my gear swap i had the AOD still in b4 i did my t5 swap. i was going to get 4.10s like everyone said with the AOD.

my stock rearend was in crappy shape. carrier was worn so i suffered from 1 wheel peels, axle was bent. So instead of working on the POS i ran across a deal for a good price. I bought a whole 8.8 that was rebuilt with 3.90 gears, ready to bolt on for 400$

the difference was amazing, gave my old gutless AOD some... guts lol then when the t5 swap was completed OMG, words couldnt describe it. the old AOD was holding back the gears. 1st was tirespin, could get sideways in 2nd loads of fun.


my friend has 373s and really u cant tell much of a difference SOTP wise. but mine hits the traps right at 5200 rpm, right where a stock 5.0 peaks HP at.

might not be a big big difference feel wise, but the track will pick up the difference. maybe 2tenths or something. you will get off the line harder, and use all gears going down the track.

3.90 seems to be an oddball ratio, but lately it seems more popular than when i had first got mine.


glad to hear u are satisfied. i think i made a good choice. youre right, 3.90 is a bit of an oddball but hey, if it works and i like it thats all that matters :D
 
I had 3.55s with my heads, intake and cam (small one at the time) car (daily) and for me it just wasnt enough gear. I ditched the 3.55s and went to 3.90s and could not be happier.

My car picked up a ton at the track with the gears. Its even better now with my new cam (TFS 1). I say do it.

The difference on the Hwy. isnt much and theres no need to be affraid to cruise at a slightly higher RPM. It will be a lil different at first because you will turn more RPM but its well worth it.
 
I know a guy with AFR 185s on a 302 and 4:30s in the back, that car is his daily driver. He can beat stock and slighty modded Auto LS1's all day. As long as the car isn't a daily driver I think you'll love the 3.90s.
 
jjd975 said:
I had 3.55s with my heads, intake and cam (small one at the time) car (daily) and for me it just wasnt enough gear. I ditched the 3.55s and went to 3.90s and could not be happier.

My car picked up a ton at the track with the gears. Its even better now with my new cam (TFS 1). I say do it.

The difference on the Hwy. isnt much and theres no need to be affraid to cruise at a slightly higher RPM. It will be a lil different at first because you will turn more RPM but its well worth it.


makes me feel better that you sorta have the setup i have and going from the same gear to a 3.90. you said you couldnt be happy with the change. now im looking foward to it
 
JBeezy53 said:
I know a guy with AFR 185s on a 302 and 4:30s in the back, that car is his daily driver. He can beat stock and slighty modded Auto LS1's all day. As long as the car isn't a daily driver I think you'll love the 3.90s.

yea, its def not a DD so it being a weekend car the gears should be enjoyable.


it will feel funny tho in 5th cruising and hearing the exhaust roar a little louder :D