Hey everyone, I'm new to the forum so I just wanted to start out by sayin hi. Anyways, I was wondering if anyone knows about any performance parts for the 3.9. I have a 99 w/ a 5-speed and I was wondering what else can be done besides cai, chips, and exhaust.

 

welcome to df...

1.7 roller rockers, cut the intake runners and clean up the heads. then slap a v8 TB on it. make it breath and it'll perform alot better.

 

Thanx for the info, but I'm not sure I understand cutting the intake runners? Also, what did you mean by clean up the heads, is that portong and polishing?

 

The intake plenum in the magnum LA-based engines is barrel shaped, and the intake runners are pretty long as they wrap around to form the barrel. You can cut the length down to raise the higher rpm power. And yeah, port/polish the heads.

 

cutting the runners will make it breath better in the upper rpms... how much to cut on a 3.9, i'm not sure. I've read that if you cut them the same as the 5.9 you'll get the best results but, you should verify this before cutting them. on my 5.9 I did 2 manifolds... 1 I cut 1.5 off and the other .5" the 1.5 performed much better than the .5.

on the heads, yes port & polish... and once you have the manifold done, match it to the heads.

 

forgot to post the pic...

[IMG]local://upfiles/1508/998690AB768E4F7F8879CFC2B2364242.jpg[/IMG]

 

Cool, thanx again! Where do you think I could read up on this to find out how much to do, I obviously dont wanna do anything todamage the intake.

 

I got a junkyard intake to cut-$60--then cut as much as I could,all the way back . Also gasket matched port side and radiused injector bores. running fastman TB 5 hole injectors 1.7 rr. idle to 2000 not as "CRISP" as stock but runs good. 2000 to 5000 is awesome. Got a superchips,auburn LSD and 4.10 's goin in to firm up the off idle performance