Has anyone done this on the board? I tried teh search nothing came up as always. Would it a better feel?

 

It sure will. Your acceleration would increase and your top end would drop. Not that its a big concern unless you like toping out your car.

 

For driveability concerns, I would use the 3.7 vs the 3.9 on the AT.

 

I wouldnt worry to much about it. I used to DD a 82 chevy p/u w/ a souped up 350 w/ 4.10 gears on a TH 350. It was not that bad. You got two more additional gears.

 

It would launch real hard but the problem i see is this,i have a 3.5 in my auto and at 70mph the engine rpm is just a hair under 3,000 rpm,s.I would hate to see what rpm,s the 3.9 would be at and your gas mileage would absolutely suck.

 

Somewhere between 3000 and 3500rpm. I suppose, I would say the lower end of it. You can always lower your cruising speed on the highway. If your worried about gas mileage, dont do it.

 

I have a 3:9 in mine and have had no problems. Over 70mph rpms are about 32-3300 give or take. But then again I dont really drive my car much

 

Why would this matter much ??

 

I don't really care about gas milage much lol. But I do care about engine wear and what not. Will it affect reliabilty? Present problems in teh future?

 

I'm not to sure. I can tell you my cousin had a fox body stang w/ 4.10 in it when he had over 75,000 mi in it and drove it like that for 2 more years before selling it.

He did not have any problems come up. Only thing was his fuel pump, but that was for another reason. I had my gears in my pickup for close to 2yrs before removing them due to throwing a 454bb into it. I had no problems whatsoever. Both engines ran strong.

 

Here's a cool gear/MPH calculator that will help you figure out RPM points for different final gear ratios.

http://www.f-body.org/gears/

.

 

I highly doubt you will have any excess engine wear.

 

I got the 3.9 in my 5at...at 80 mph I am around 3700-3800 rpms...its high up there...gas has gone down, but I knew that would happen

 

How does the acceleration differ from having your "stock" gears ??
Is it a "substantial" gain, or just a "little" gain ?
...or I should ask, was it worth the time and effort (and expense) ???

 

I did it almost a year and a half ago. Love it, go do it and don't whine about how high your engine revs if you drive 80-90mph all the time. </thread>

 

after two years of the car not shifting like it used to, hitting the rev limiter most of the time (revs fast as hell in first) and lower gas mileage...I would still say get it...its the best money i spent/technically lost (gas cost)...but its also due to the way i drive...depends on how you drive....

 

Ide love to at least get the 3.5 from a manual. Would hate to lose cruise control even though i never use it, maybe one a month if i visit a friend. I love how long the gears rev out but would be nicer to be a little quicker in the low end. I'm not a big top end guy, not looking for big speeding tickets.

 

Wait, if you get a high FD, you'd lose teh cruise control function? Ergh...
but that aside. What brand are you guys using. And about how much was the cost of installation?

 

The loss of cruise control, from what I have read and considering I have an AT, is only on the AT's.

As I have said to others; it is the best NA mod in imo.

The only drawbacks with this mod are:

1. Getting a hold on the actual 3.9 gears ( I waited roughly 6 months for the Central 20 gears)

2. If you have an AT, swapping pumpkins with a MT.

3. Install takes time and should be installed by a gear specialist. And in some cases extra parts may need to ordered. My car was in the shop for 7 days.

4. Gas mileage varies. I'm averaging 17mpg in the city.

5. If it's an AT the cruise control will more than likely not work.

 

hmmm...how much did it set you back?