I know MMS is the only supply I've seen for headers for the 6th gen, and they don't want to build them because they're not in high demand.

So does anyone have PEMs? I already have PIMs, so would this be a good choice?

 

I think you can make any 3800 headers fit as long as they're for a W body. If you have a 3800 just google something like 3800 headers Monte Carlo and it should say what will fit.

I'd try to go with a Plog as opposed to PEMs.

 

Are you sure? And Plog is short for power logs, right?

 

I would suggest just porting the exhaust manifolds. I lost quite a bit of low end power with headers. Plus they were a pain to get fit correctly, which they actually still dont fit properly. They rest against my fan motor and have melted a bit of the shroud. Having shorter engine mounts doesnt help but the melting occured before I installed those anyway.


EDIT: DNA Motoring is the company I got my headers from.

 

Okay. I know it's a tight fit in that engine bay so I'll go ahead with porting the exhaust manifolds.

 

While I agree it is possible to do, I think it would be prohibitively expensive unless he knows someone with fab skills or just wants them at any cost.

IIRC he has a 3400, not a 3800. The bolt pattern is different, the head angle is different, and the port spacing is different (3400's middle port isn't centered like the 3800, its offset to one side).

 

Thinking outside of the box a bit as the 3400 continued on in its evolution (whereas the 3800s stopped).

What about using 3500 manifolds instead?

Pulling up pictures on Google, the manifold I found for a 3400 v6 looks horrendous for NA performance (maybe OK as a turbo log). But the stock 3500 manifolds are much closer to a shorty header, at least up front.

Being the same engine family, perhaps at least they'd bolt up? It also looks like manifolds interchange between 3500 and 3900, so these should easily support 230+ crank hp.

 

Ohhh in that case disregard what I've said, I thought it was a 3.8

 

I forgot that myself however everything I said still stands but even more.

I put headers on my 3400 way back and it was just awful! No torque, no power, and just an overall waste of money but a good lesson learned so...

On a more positive note, that thing is going to sound awesome at startup and idle with ported manifolds with that 3400.

 

Just curious, have you seen dyno results on 3400 PEMs? That front manifold looks horrendous if the picture I found was accurate.

I'm just not familiar at all with the 60* engines and would hate to lead the OP to waste money on something that doesn't have verifiable gains.

Did you happen to dyno before/ after - or determine a cause? I know there were people that ran into that kind of stuff in the early 3800 NA modding too. Some of the stuff would pick up power way up at the tippy top but tank it everywhere else and end up with a negative average.

You'd think some type of header would benefit the 60* engine as you can actually get scavenging benefits unlike the oddball firing order of the 3800. Curious if they were designed poorly (primaries too big, too short, etc).