I am going to change out my gears and get a level 10 torque converter and Valve body at the same time.

I was wondering if anyone has skipped the 3.5 and went straight to the 3.9 on the automatic tranny?

I don't care about loosing top speed... here in south florida laws are getting insane about that anyway.

What problems would i encounter, and how come i haven't seen this yet... am i missing something?

BTW, does anyone know the actuall specifics on how short the gears would be in the 3.5 vs the 3.9?
Thanks a lot,
-Eric

 

It would be pretty aggressive and I think the reason you haven't seen it is that the 5th gear on an auto is not as tall as 6th on the MT cars so your cruising rpms would be pretty high thus decreasing gas mileage quite a bit. For an NA track car it might work out. A 3.7 FD would be a nice solution for the 5AT cars, but that is not an option. The 3.5 is a nice bump for an NA car but doesn't sacrifice gas mileage on the highway.

 

I agree.

 

Unless you are seriously tracking the car with the auto...I would go with the 3.5.
That is jsut my 2 cents.
The next batch of gears ETA is July 15th.....and there is all ready a list forming.
Cheers
BJ@350EVO.com

 

^ Nice.
Thanks for the reply's ya'll.

What gears are you looking at producing next. I want something a little more aggresive then the 3.5, mabye a 3.6, or 3.7 would be great.

a 3.1 for the serious FI guys and a 3.7 for the NA guys would be great.
Thanks again.
-Eric

 

At this time we do not plan on pruducing any other final drive......the 3.9 was designed for NA applications.
BJ@350EVO.com

 

Some of you are saying 3.5 is a good choice for NA applications. What about a 5AT with APS's ST. Still a good idea?

-Mark

 

If you're going F/I, you better stay with the 3.3 FD, or you may have traction issues. I've seen that mentioned dozens of times, including comments from folks who lamented the fact they had switched away from the 3.3...