I 'm in the process of putting a HE351 on my truck. I' m currently running the MBRP 4" exhaust but I have a stock 3.5" downpipe. I 'd like to step it up to a 4" DP and run a 4" exhaust to a single stack.

I really don't want to spend alot on the exhaust, not much at all really. Anyone here running flexpipe up to the stack? Is a muffler needed for a setup like this? Any suggestions are much appreciated. Pics would be nice also!

Is there a clamp available to hold the stack secure to the bed somehow?

Thanks.

 

No suggestions here?

*I called Banks today looking for a 4" DP and they wanted $210, that seems a little steep for just a DP, any one know a better place to get one?

 

just about anybody is cheaper than banks . grand rock seems to have some pretty nice stuff fairly priced. as far as downpipe goes u could probably get a explandit if your looking to save money. as far as piping i would go to your local big rig shop. mack dealer etc..they have the piping you need on the shelf....

 

Your saying they can expand my 3.5" outlet to a 4" outlet? I don't think that would work, I still need to have that lip there to couple to the flange on the exhaust. Maybe im missing something here.

If push comes to shove I can just run the HE351 with what I have now and always switch to a true 4" later on. I'd just like to do it now since I already have the thing torn apart.

*Has anyone here done some mild porting to the exhaust manifold flanges? Nothing to in depth, just making the holes a little more rounded? Is there anything to be gained from this?*

 

Get a stock 4" downpipe, if you werent so far away id say you can have my stocker off my '07....

That or just get a reducer from 4" to 3.5" and run straight 4" pipe back to where your stack goes, and run as little flex as possible(if you dont want drone) the more you run, the more resonance youll have in the truck just because of the flexpipe. Youll also have some too just from a4" straight pipe being a hair nastier than 5"s that ive experienced. 5" has a more mellow tone.

Just get a 90* 4" elbow too and you're set, shouldnt be more than $100 if you use the stock downpipe, maybe a hair more if you have to fine one.
Im assuming youll use the '04.5+ elbow too?(why not use the newer downpipe?)

Oh, check out airflo.com for reducers/elbows/etc, great prices...

 

Well I got the HE351 from my fathers 04.5 but he already has a 5" exhaust on the truck and he installed a HTT turbo recently. So he still has his stock DP on.

That's another thing I was thinking about, If I can help it I really don't want all of that drone in the cab. I dunno if a muffler can be used for a setup like this, is there even enough space for one?

Sending you a PM Pooter.