3:90 Diff Chime In
Race Director
Joined: Jun 2004
Posts: 19,459
Likes: 48
From: Schaumburg IL
CI 7-8-9-11 Veteran
St. Jude Donor '06-'10, '13
I just got 390's (mn6 trans) and I love them. I thought of 410's, but might be adding a lot more power next year, so I set 390 as my limit. I can definitley feel the difference from the 342. Car pulls great ( I also have heads,cam, headers).
Anything specifically you want to know?
Anything specifically you want to know?
Race Director
Joined: Dec 2004
Posts: 13,760
Likes: 75
From: Haymarket VA
I just got 390's (mn6 trans) and I love them. I thought of 410's, but might be adding a lot more power next year, so I set 390 as my limit. I can definitley feel the difference from the 342. Car pulls great ( I also have heads,cam, headers).
Anything specifically you want to know?
Anything specifically you want to know?
I had them with my 460RWHP 346 and now with my 500+RWHP 403. They are the perfect gear. Make 6th more usable and the car much better at cruise...to say nothing about acceleration. 
Instructor
Joined: Aug 2006
Posts: 107
Likes: 0
From: Boca Raton, FL
Absolutly love them! Completely changed the way the car performs out of the hole. Only downside is you'll take a hit on gas mileage. Should add a high stall when you do it. You won't be sorry.
Thread Starter
Racer
Joined: Apr 2005
Posts: 475
Likes: 1
I just got 390's (mn6 trans) and I love them. I thought of 410's, but might be adding a lot more power next year, so I set 390 as my limit. I can definitley feel the difference from the 342. Car pulls great ( I also have heads,cam, headers).
Anything specifically you want to know?
Anything specifically you want to know?
1. Top-end pull from 30, 60 and 70 MPH?
2. Range of expected 0-60MPH time?
3. How bad is MPG? I currently get 16.5 city and 26 hwy under ave use
4. 1/4 mile range of expted time? 13's, 12"s? (with my set up?) (I know many varibles. I am ave dragster at best)
Last edited by 1badc5GoStrong; Aug 24, 2007 at 12:59 PM.
Race Director
Joined: Jun 2004
Posts: 19,459
Likes: 48
From: Schaumburg IL
CI 7-8-9-11 Veteran
St. Jude Donor '06-'10, '13
I assume bottom end pull is great, what about the following:
1. Top-end pull from 30, 60 and 70 MPH?
2. Range of expected 0-60MPH time?
3. How bad is MPG? I currently get 16.5 city and 26 hwy under ave use
4. 1/4 mile range of expted time? 13's, 12"s? (with my set up?) (I know many varibles. I am ave dragster at best)
1. Top-end pull from 30, 60 and 70 MPH?
2. Range of expected 0-60MPH time?
3. How bad is MPG? I currently get 16.5 city and 26 hwy under ave use
4. 1/4 mile range of expted time? 13's, 12"s? (with my set up?) (I know many varibles. I am ave dragster at best)
I'll try and comment on the other areas.
1-Pull from 0-30 and 0-60 is great, even 60-75 still pulls good..you'll start to notice a small difference above 75, not loss of power, but you'll notice how the 342 is more comnfortable less RPM if you willl, but again nothing concerning.
2- MPG, I think depends alot also on your driving syle. I have a 6 speed, and my city MPG actually went up from about 18mpg to 19mpg, probably because I can use higher gears (5th and 6th) more often and that drops the r's down a bit. I think some people reallly make a bigger deal out of MPG loss,than it really is. 410's is where I think you'll notice a lot bigger difference in MPG loss.
Race Director
Joined: Dec 2004
Posts: 13,760
Likes: 75
From: Haymarket VA
The cam I had in my 346 got it's best MPG at 80MPH. With the 3.90's I got the best MPG at 74MPH. A little safer (LE)anyways. 
I've always said the M6 cars should have come with 3.90's from the factory.
I've always said the M6 cars should have come with 3.90's from the factory.
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