I have a 03 5at should i go with the 3.5 Fd they offer from 350evo or does the 3.9 fit the automatic as well.

 

A lot of folks will tell you to go 3.5 for gas milage, but if you want really agressive gearing and the most "throw you back" feel, go for the 3.9.

 

From what I understand, you can not put the 3.9 gears in the 3.3 housing without a lot of work. It is better to swap your 3.3 for someone who is F/I that has a 3.5. The cost for me to do this was labor and shipping costs, about $250 in all. If you are planning on going F/I in the future, you may want to stay at a 3.5, especially if you are wanting to go with a turbo setup. I am not aware of anyone with a 5AT, F/I and the 3.9 gears. I know some are in the works (Sentry65 I think).

Anyway, go with the 3.5 first and then move up later after you have made up your end performance goals!

I have a 5AT and a Vortech SC and cut roughly .3 sec off my 1/4 time just with this swap.

 

You can always get a 3.9 complete with Pumpkin on core charge. Probably the easiest way to swap.

 

I have been in a Z with the 3.9 FD, Stillen stage 2 SC, Stillen upgraded trans valve body, Stillen heeaders and TD exhaust, Nismo wheels, and LSD. I must say I loved it. The rear on this car was done as a complete pumkin. No real traction issues in a straight line. Tires on the back were Goodyear Eagle F1 275/40R18. I think the tires with the LSD helped alot. Awsome acceleration.